Which of the following is not true for fertilisers?

The process of conversion of sugar into alcohol is called

The material similar to silk in appearance is

Materials which can be drawn into wires are called ductile. Which of the following is not a ductile material?

When coal burns in air

An agricultural implement used since ancient times for tilling the soil, adding fertilizers, removing weeds etc. is :

Which of these does not prevent growth of bacteria?

The most suitable material for the preparation of handles of cooking utensils is

Materials which can be drawn into wires are called ductile. Which of the following is not a ductile material?

Which substance is formed by the carbonisation of dead vegetation?

Which of the following is not true for fertilisers?

Cocci are __________ shaped bacteria.

Fireproof plastic used in the uniform of fireman is:

Metals can be cut with a knife:

Naphthalene balls are obtained from coal tar and are used as

Which of the following is not a traditional method of irrigation?

The following is an antibiotic

Which is not a property of plastic?

Boojho has learnt that non-metals on beating with a hammer are generally broken into pieces.Which of the following is non-metal?

Purest form of carbon is

Watering the crops is called

Paheli dug two pits, A and B, in her garden. In pit A, she put a polythene bag packet with some agricultural waste. In pit B, she dumped the same kind of waste but without packing it in a polythene bag. She then covered both the pits with soil. What did she observe after a month?

Pick the synthetic fibre out of the following.

Metals are not used in making:

A black, tough and porous substance is :

The following is an antibiotic

Which of these do not have a regular cell structure?

Cocci are __________ shaped bacteria.

This bacterium promotes the formation of milk into curd:

Which is not a communicable disease?

Watering the crops is called

Planting of seeds is called

Which of the following tools would a farmer use to remove weeds from the field?

Process of separating grain seeds from the chaff is called:

Which of the following is not a traditional method of irrigation?

Which of the following statements is not true for organic manure?

Watering the crops is called

2,4-D is a

The monsoon season in our country is during the months

The use of manure (which is not correct) :

You must have heard farmers talking about soil fertility. What is it? Mention some methods by which soil fertility can be replenished.

Explain various agricultural practices in sequential manner.

Observe the figure and answer the following questions.

(a) Name the microorganism and the group to which it belongs.
(b) Name the food item on which the organism grows.
(c) Does it grow well in dry or in moist conditions?
(d) Is it safe to eat infected bread?

What do you understand by food preservation?
Explain any four methods of food preservation.

Iron is more reactive than copper. Can you write an activity to show this?

Write a paragraph in your own words on each of the following - Preparation of soil

Write a paragraph in your own words on each of the following - Threshing

State two advantages of using chemical fertilisers over manures. What would happen if fertilisers are used in excess?

What is the role of water in the production of crops?

Write a short paragraph on the harmful effects of microorganisms.

Give example of Rabi crop

Give names of two traditional methods and two modern methods of irrigation

Is there any advantage of using a cultivator?

What are organic foods?

How can a farmer increase the fertility of the soil?

What do CFCs stand for? Name some devices where CFCs are used. Why CFCs are considered as pollutants?

Arjun while travelling with his father saw the same message displayed at every traffic signal. The message was 'stop the vehicle engine at the red lights to save the fuel'. He noticed his father turning the engine off at each signal. He was confused to see this and asked his father
(a) It is recommended to stop the vehicle engine at the red light signals. Give reason.
(b) Suggest the process associated when vehicle engine is ON.
(c) What values are government trying to inculcate in people with the message?
(d) Will you support the message? Why?
(e) Mention the values shown by Arjun.

We should plant trees and nurture the ones already present in the neighbourhood. Why?

Read the paragraph and answer the questions following it.
Water is essential for life. Without water there would be no life. We usually take water as granted for its purity, but we must ensure the quality-of water. Pollution of water originates from human activities. Through different paths, pollution reaches to groundwater. Easily identified source or place of pollution is called as point source, e.g. municipal and industrial discharge pipes, where pollutants enter the water source. Non-point sources of pollution are those where a source of pollution cannot be easily identified, e.g. agricultural run-off, acid rain, etc.
(a) How do you classify the various sources of water pollution?
(b) What are the point sources of water pollution?
(c) Name any two non-point sources of water pollution?

An Indian holy river is among the ten most endangered rivers list of WWF. Which is it? How is the water of this river polluted?

Give a reason, why the stars are visible only at night

Last week, Ramesh (a science teacher) was teaching about the planets to his students of class 5th• After giving a small lecture on planets, he started cross questioning with his students on the same topic. He found that almost, all the students answered all the questions. He asked following questions:
(i) Give the names of all the planets of solar system with respect to their distance from the Sun.
(ii) Name the planet on which the life is known to exist.
(iii) Mention the values shown by students of Ramesh here.

Figure shows comets without their tail. Show the tails of the comets at positions A, B, and C. In which position will the tail be longest?

Explain the difference between a natural and an artificial satellite. Enlist any three applications of artificial satellite.

Explain in brief about planets. How is a planet differ from a star?

Boojho planned an activity to observe an object A through pipes as shown in figure so that he could see objects which he could not directly see.

(a) Mention how many mirrors should he use to see the objects.
(b) Indicate the positions of the mirrors in the figure.
(c) State what must be the angle w.r.t. the incident light at which he should place the mirrors.
(d) Indicate the direction of rays in the figure.
(e) If any of the mirrors is removed, will he be able to see the objects?

Explain the process which enables us to perceive motion in a cartoon film.

A man stands 10m in front of a large plane mirror. So, how far must he walk before he is 5 m away from his image?

How is the phenomenon of reflection used in making a kaleidoscope? What are the applications of a kaleidoscope?

Aditya visited a lake on two days. On the first day, the reflection of the surrounding mountains could be seen clearly in water of the lake. On the second day, he was not able to see the reflection of the mountains clearly. Give one possible reason for this phenomenon and explain your answer clearly.

Explain how lightning takes place.

Explain why it is safer to use a wireless telephone instead of a land line telephone during lightning.

During lightning, if you are outside the house, then what precautions would you take?

Priya went to the school with umbrella on rainy season. One day, while returning from the school the rain started on the way. Priya opened her umbrella and saved himself from rainwater. After some time, she observed some lightning sparks in the sky. Sudden, she folded her umbrella and went to a shelter under a closed building.
(a) State the cause of lightning.
(b) Priya folded her umbrella. Explain why.
(c) Mention the method opted by Priya here.

In year 2013, there was a showcase in IIT Hyderabad. All the students from different schools and colleges were invited on that occasion. Naveen with his friends went to see the projects made by M.Tech students. He found a project based on the construction of anti-earthquake buildings in which the small houses of iron rods was constructed. One house was with a hose containing water and the other was without hose.
They shocked on shaking both the houses.
(a) Describe an earthquake.
(b) Explain the meaning of quake-resist building.
(c) Mention which force reduces the shaking in a building with hose.
(d) State the feeling about the students who showed his project.

Discuss two methods of testing a conductor or an insulator

In the circuit given in the figure, Boojho observed that copper is deposited on the electrode connected to the negative terminal of the battery. Paheli tried to repeat the same experiment. But she could find only one copper plate. Therefore, she took a carbon rod as negative electrode. Will copper be still deposited on the carbon rod? Explain your answer.

You are provided with a magnetic compass, an empty matchbox, a battery of two cells and connecting wires. Using these objects, how will you make a tester for testing an electric circuit? Draw the necessary circuit diagram and explain.

Prove that lemon juice and vinegar are good conductors of electricity.

Observe the circuit given in figure.

Boojho set up this circuit for purification of copper. What will be the nature of
(a) plate A
(b) plate B
(c) and the solution. Explain the process of purification

Mention the property of vibrations which determine the pitch of the sound. Briefly explain along with some examples.

How is sound produced and how is it transmitted and heard by us?

Explain in detail how sound travel slower than light.

An alarm bell is kept inside a vessel as shown in figure. A person standing close to it can distinctly hear the sound of alarm. Now, if the air inside the vessel is removed completely, how will the loudness of alarm get affected for the same person?

Explain in brief about eardrum. Also explain how does it play an important role in hearing.

Mention three examples that show that friction produces heat.

In physics period a teacher told his students that when a cricket player wants to catch a ball then first he rubs the hands. Thus, there is less chance of slipping the ball from hands.
(i) Explain the reason of not slipping of ball from hands.
(ii) If the player makes his hands oily instead of rubbing them, would he be able to catch the ball?
(iii) Mention the types of teaching skills of teacher being represented here?

Explain with the help of an example that heat is produced by friction.

We have two identical metal sheets. One of them is rubbed with sand paper and the other with ordinary paper. The one rubbed with sand paper shines more than the other. Give reason.

Explain some examples where we have to reduce the friction.

Describe each effect of the force given below with one example.
(i) Make an object move from rest.
(ii) May change the speed of an object.
(iii) May bring about a change in the shape of an object Ans.

In walking the pressure on the ground is more as compared to that in standing on the ground. Explain this statement.

Briefly explain the concept of variation of atmospheric pressure.

Two women are of the same weight. One wears sandals with pointed heels while the other wears sandals with flat sales. Which one would feel more comfortable while walking on a sandy beach? Give reasons for your answer .

Observe the vessels A, B, C and D as shown in figure carefully.

Volume of water taken in each vessel is as shown. Arrange them in the order of decreasing pressure at the base of each vessel. Explain.

'Brick and cell are one and the same'. Explain this sentence.

(a) A jelly-like substance is present in a cell. What is it called as? Also give its function.
(b) Give the meaning of protoplasm. Name the four elements which make up major part of protoplasm.

A cell has A as its control centre. A contains B that plays an important role in inheritance with the help of C. The cell also contains a jelly-like substance D. D contains various cell organelles like E that is essential for obtaining energy from food. The cell is surrounded by an F that is a living component. What could A, B, D, E and F be? Also write a short note on C.

The following is a brief paragraph based on cells, their structure and function, provide the missing terms and write one line about each. A biologist was looking at a cell with a ...(i)... He observed the presence of small green structures called ______(ii) __________ These structures are important as they provide the cell with __________ (iii)__________ that helps in the process of (iv) ________ The outer boundary of the cell is __________ (v) , which holds the cell together.

In walking the pressure on the ground is more as compared to that in standing on the ground. Explain this statement.

Two women are of the same weight. One wears sandals with pointed heels while the other wears sandals with flat sales. Which one would feel more comfortable while walking on a sandy beach? Give reasons for your answer .

Observe the vessels A, B, C and D as shown in figure carefully.

Volume of water taken in each vessel is as shown. Arrange them in the order of decreasing pressure at the base of each vessel. Explain.

It is difficult to cut cloth using a pair of scissors with blunt blades. Explain.

In physics class teacher ask to his student that a man carrying a load of 50 N in his hand pulling it. The area of palm where the load act is 5 cm². Then
(a) Determine the pressure acting on the fingers of man.
(b) Also, find the pressure acting if the man carrying the same load by keeping it on the shoulder occupying an area of 50 cm².
(c) Mention the type of teaching skill of teacher is being represented here?

Boojho planned an activity to observe an object A through pipes as shown in figure so that he could see objects which he could not directly see.

(a) Mention how many mirrors should he use to see the objects.
(b) Indicate the positions of the mirrors in the figure.
(c) State what must be the angle w.r.t. the incident light at which he should place the mirrors.
(d) Indicate the direction of rays in the figure.
(e) If any of the mirrors is removed, will he be able to see the objects?

Explain the process which enables us to perceive motion in a cartoon film.

There is a mistake in each of the following ray diagrams given as figure (a), (b), and (c). Make the necessary correction(s).

Two students of your class brought three big plane mirrors in their classroom for science fair. They fixed the three mirrors. One at the ceiling and the other two on the adjacent walls of the room. Since every student was able to see six images of himself/herself. Students of other classes also come to see this and felt happy. A student of class VII was determined to know the reason behind it. He went to the library, consult other students and next day come up with the correct answer.
(a) Mention the value were depicted by the students of class VII?
(b) Also, give the reason for seeing six images.

How is the phenomenon of reflection used in making a kaleidoscope? What are the applications of a kaleidoscope?

What do CFCs stand for? Name some devices where CFCs are used. Why CFCs are considered as pollutants?

Arjun while travelling with his father saw the same message displayed at every traffic signal. The message was 'stop the vehicle engine at the red lights to save the fuel'. He noticed his father turning the engine off at each signal. He was confused to see this and asked his father
(a) It is recommended to stop the vehicle engine at the red light signals. Give reason.
(b) Suggest the process associated when vehicle engine is ON.
(c) What values are government trying to inculcate in people with the message?
(d) Will you support the message? Why?
(e) Mention the values shown by Arjun.

We should plant trees and nurture the ones already present in the neighbourhood. Why?

Read the paragraph and answer the questions following it.
Water is essential for life. Without water there would be no life. We usually take water as granted for its purity, but we must ensure the quality-of water. Pollution of water originates from human activities. Through different paths, pollution reaches to groundwater. Easily identified source or place of pollution is called as point source, e.g. municipal and industrial discharge pipes, where pollutants enter the water source. Non-point sources of pollution are those where a source of pollution cannot be easily identified, e.g. agricultural run-off, acid rain, etc.
(a) How do you classify the various sources of water pollution?
(b) What are the point sources of water pollution?
(c) Name any two non-point sources of water pollution?

An Indian holy river is among the ten most endangered rivers list of WWF. Which is it? How is the water of this river polluted?

Explain how lightning takes place.

Explain why it is safer to use a wireless telephone instead of a land line telephone during lightning.

During lightning, if you are outside the house, then what precautions would you take?

Priya went to the school with umbrella on rainy season. One day, while returning from the school the rain started on the way. Priya opened her umbrella and saved himself from rainwater. After some time, she observed some lightning sparks in the sky. Sudden, she folded her umbrella and went to a shelter under a closed building.
(a) State the cause of lightning.
(b) Priya folded her umbrella. Explain why.
(c) Mention the method opted by Priya here.

In year 2013, there was a showcase in IIT Hyderabad. All the students from different schools and colleges were invited on that occasion. Naveen with his friends went to see the projects made by M.Tech students. He found a project based on the construction of anti-earthquake buildings in which the small houses of iron rods was constructed. One house was with a hose containing water and the other was without hose.
They shocked on shaking both the houses.
(a) Describe an earthquake.
(b) Explain the meaning of quake-resist building.
(c) Mention which force reduces the shaking in a building with hose.
(d) State the feeling about the students who showed his project.

Mention the property of vibrations which determine the pitch of the sound. Briefly explain along with some examples.

How is sound produced and how is it transmitted and heard by us?

Explain in detail how sound travel slower than light.

An alarm bell is kept inside a vessel as shown in figure. A person standing close to it can distinctly hear the sound of alarm. Now, if the air inside the vessel is removed completely, how will the loudness of alarm get affected for the same person?

Explain in brief about eardrum. Also explain how does it play an important role in hearing.

Write notes on—
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.

The table below shows the data on likely heights of boys and girls as they grow in age. Draw graphs showing height and age for both boys and girls on the same graph paper. What conclusions can be drawn from these graphs?

Amit was very good in study. But as he attained the age of 13 years, he became dull and lethargic. Asked by his teacher, Amit told that he is very worried about the changes that are taking place in his body such as hoarse voice, height, etc. The teacher smiled and explained that it is a normal process of growing up.
(a) Mention some of the changes that Amit must be going through.
(b) What is this special period of life known as?
(c) Can you explain the reason of his hoarse voice?
(d) What is responsible for these changes?
(e) Identify the values shown by his teacher.

Observe the chart and graph given in figure carefully and answer the following questions.

(a) Which of the line represents the height of boys?
(b) Which line represents the height of girls?
(c) What is the difference between the pattern of increase in the height of boys and girls?
(d) Is this pattern true for each individual?

During adolescence, the body of boys and girls undergoes certain changes. Given below are few of those changes
(a) Broad shoulders
(b) Wider chests
(c) Wider region below waist
(d) Development of muscles
(e) Development of mammary glands
(f) Growth of facial hair
(g) Acne and pimples on face
(h) Development of sex organs
(i) High-pitched voice
(j) Growth of pubic hair
Categorise these changes into those that occur in boys and those that occur in girls and fill in the table given below.
Body changes during adolescence

How can we prevent the following diseases?
(a) Cholera (b) Typhoid (c) Hepatitis-A

Give causative microorganism, mode of transmission and one preventive measure Qf human diseases like Polio, Cholera and Hepatitis-B.

During biology class, teacher was telling about microbes and how they are useful to humans. Hearing this, Jasmine got confused as she knew the TB caused to her uncle is due to a microbe. She asked his teacher about it. The teacher appreciated her for question and explained the whole class.
(a) What are microbes?
(b) How are microbes helpful to humans?
(c) Name one microbe
(i) used in household products.
(ii) used in antibiotics.
(d) Mention two diseases other than TB caused by microbes.
(e) Identify the values shown by Jasmine.

Observe the figure and answer the following questions.

(a) Name the microorganism and the group to which it belongs.
(b) Name the food item on which the organism grows.
(c) Does it grow well in dry or in moist conditions?
(d) Is it safe to eat infected bread?

Write a short paragraph on the diseases caused by micro-organisms.

Write notes on—
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.

The table below shows the data on likely heights of boys and girls as they grow in age. Draw graphs showing height and age for both boys and girls on the same graph paper. What conclusions can be drawn from these graphs?

During adolescence, the body of boys and girls undergoes certain changes. Given below are few of those changes
(a) Broad shoulders
(b) Wider chests
(c) Wider region below waist
(d) Development of muscles
(e) Development of mammary glands
(f) Growth of facial hair
(g) Acne and pimples on face
(h) Development of sex organs
(i) High-pitched voice
(j) Growth of pubic hair
Categorise these changes into those that occur in boys and those that occur in girls and fill in the table given below.
Body changes during adolescence

In figure, mark the position of the endocrine glands which release the hormones that
(a) control the release of sex hormones.
(b) are responsible for the secondary sexual characters in boys.
(c) prevent diabetes.
(d) maintain the correct salt balance in the blood.

It is believed that height of a child depends upon the genes inherited from parents. However, it is often seen that tall parents may have short children and vice-versa. Are these factors other than genes that can cause these variations?

After observing figure above, answer the following.
(a) Read the following statements and label them in the figure.
(i) The part which produces female gametes.
(ii) The part where development of the baby takes place.
(iii) The part through which the developing embryo passes to reach the uterus.
(b) Explain the future development of the embryo that would take place after it gets embedded in the uterus.

How can we say that fish exhibits external fertilisation?

Observe the following figures.

(i) Identify the stages (a) to (d) in figure during development of human baby.
(ii) Arrange the stages in correct sequence of development.
(iii) Explain the development that takes place in anyone stage.

(a) Give the term used for the fusion of gametes.
(b) Name the type of fertilisation in humans
(c) Where does it mainly occur?
(d) Fertilisation in humans takes place'ln female. How?

Explain the process of reproduction in human beings with suitable diagrams.

We read about various organelles present in a cell. Explain what is an organelle. Name the organelles that are found in most cells. What is the function of nucleus?

'Brick and cell are one and the same'. Explain this sentence.

(a) A jelly-like substance is present in a cell. What is it called as? Also give its function.
(b) Give the meaning of protoplasm. Name the four elements which make up major part of protoplasm.

A cell has A as its control centre. A contains B that plays an important role in inheritance with the help of C. The cell also contains a jelly-like substance D. D contains various cell organelles like E that is essential for obtaining energy from food. The cell is surrounded by an F that is a living component. What could A, B, D, E and F be? Also write a short note on C.

The size of the cells of an organism has no relation with the size of its body. Do you agree? Give reason for your answer.

What are the advantages of Aeforestation?

How is recycling and saving of papers related to deforestation?

Is deforestation associated with global warming? Explain.

Deforestation leads to frequent floods and droughts. Give a proper explanation in support of the statement.

Seeing a crowd of students in one corner of the school, the principal rushed to see the matter and found some children beating and chasing a small lizard. On seeing the principal, all the children fled to their classes except Alok who requested the principal to arrange for some medical assistance for the injured animal. The principal rewarded him for his attitude.
(a) Species of few animals are very less in number. What are these species known as?
(b) Mention the threat to biodiversity.
(c) It is wrong to harm the animals. Give reason.
(d) Give example of some endemic species of India. 
(e) Identify values shown by Alok.

At an individual level, how can you help to reduce air pollution?

Clear, transparent water is always fit for drinking. Comment.

Prepare a brief speech on global warming. You have to deliver the speech in your class.

Describe the threat to the beauty of the Taj Mahal.

By the end of 2002, public transport of Delhi switched over to a new fuel. Name the fuel. Why is this fuel considered better?

Gurmit wanted to perform Activity using a laser torch. Her teacher advised her not to do so. Can you explain the basis of the teacher’s advise?

Explain how you can take care of your eyes.

What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?

Boojho stands at A just on the side of a plane mirror as shown in figure. Can he see himself in the mirror? Also can he see the image of objects situated at P, Q and R?

(a) Find out the position of the image of an object situated at A in the plane mirror.
(b) Can Paheli at B see this image?
(c) Can Boojho at C see this image?
(d) When Paheli moves from B to C, where does the image of A move?

Does pure water conduct electricity? If not, what can we do to make it conducting?

In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. Explain why they do this.

A child staying in a coastal region tests the drinking water and also the sea water with his tester. He finds that the compass needle deflects more in the case of seawater. Can you explain the reason?

Explain in brief the procedure of glowing of bulb in a liquid

Explain, how can we purify the impure metals

Explain the process, how bat sure ultrasonic waves to catch a prey

Explain the consequences noise pollution

List three sources of noise pollution in your locality

We have learnt that vibration is necessary for producing sound. Explain why the sound produced by every vibrating body cannot be heard by us.

Briefly explain total hearing impairment.

Explain the reason in brief for not existence of life on the mercury planet.

The stars appear to move from east to west,explain why with the help of a reason.

The moment, the meteors enter the atmosphere of Earth, then what exactly happens? Explain in brief.

Explain the reason of changing of shape of moon everyday.

Explain the difference between a star and a shooting star in a tabular form.

Explain why sliding friction is less than the static friction.

Give examples to show that friction is both a friend and a foe.

Explain why objects moving in fluids must have special shapes.

You might have noticed that when used for a long time, slippers with rubber soles become slippery. Explain the reason.

Is there a force of friction between the wheels of a moving train and iron rails? If yes, name the type of friction. If an air cushion can be introduced between the wheel and the rail, what effect will it have on the friction?

A chapati maker is a machine which converts balls of dough into chapatis. What effect of force comes into play in this process?

What is the state of motion? How can we change the state of an object?

Enlist the types of contact forces.

A ball rolling along the ground gradually slows down and finally comes to rest Why does this happen? What is the effect of this force?

Enlist the types of non-contact forces.

The weather department has predicted that a thunderstorm is likely to occur on a certain day. Suppose you have to go out on that day. Would you carry an umbrella? Explain.

During the construction of a building, the lightning conductor was left hanging in the air by mistake. Would the lightning conductor be still effective? Explain.

Explain how does lightning conductor protect a building from getting struck by lightning.

Identify the lightning conductor and the copper plate in figure.

You might have observed on a dry day that when you touch the screen of a television or computer monitor (with picture tube), you get a slight shock. Why does it happen?

Although wood has a very high calorific value, we still discourage its use as a fuel. Explain.

Manu was heating oil to fry potato chips. The cooking oil all of a sudden caught fire, he poured water to extinguish the fire. Do you think, this action was suitable? If yes, why? If not, why not? In such a condition what should Manu have done?

'Charcoal is a better fuel than wood'. Explain.

Give two examples each for a solid, liquid and gaseous fuel along with some important uses.

How can you burn wood or coal using kerosene oil?

Name the products obtained and their uses when coal is processed in industry.

Why petrol is exhaustible natural resource whereas sunlight is not? Explain.

We read in newspapers that burning of fuels is a major cause of global warming. Explain why?

We say fossil fuels will last only for a few hundred years. Comment.

The material X is a fossil fuel. It is formed from the buried large land plants (vegetation) by a very slow process Y. When X is heated in the absence of air, i. e. in the process called Z, it gives three products A, B and C. A is used as a reducing agent in the extraction of metals, B is used as an industrial fuel, whereas the product C has been traditionally used for metalling the roads. It is now replaced by a petroleum product, bitumen. Now give the answer of the following questions.
(a) What is the material X?
(b) What is the physical state and colour of X?
(c) Name the processes Y and Z.
(d) What are the products A, B and C?

What is the term used for chemical secretions of endocrine glands responsible for changes taking place in the body?

What are sex hormones? Why are they named so? State their functions.

A ten years old boy is 130 cm tall. If the present height of the boy is 78% of his full height, calculate the full height by which the boy will eventually reach at the end of growth period.

Rama is 13 years old. She is getting pimples on her face these days about which she is worried. Can you explain why she is getting pimples during this age?

Give the definition of adolescence as stated by the WHO. Why is adolescence also called teenage?

Explain the importance of reproduction in organisms.

Describe the process of fertilisation in human beings.

Give two differences between a zygote and a foetus.

Choose the most appropriate answer.
The number of nuclei present in a zygote is
(i) none
(ii) one
(iii) two
(iv) four

In which female reproductive organ does the embryo get embedded?

Write short notes on the following.
(a) Cytoplasm
(b) Nucleus of a cell.

‘Cells are the basic structural units of living organisms’. Explain.

Is the following statement correct? If it is wrong, correct the statement "Unicellular organisms do not respire, only multicellular organisms respire".

Write some point of differences between plasma membrane and cell wall.

Observe the following figure given below

Answer the following questions.
(a) Does it represent a plant cell or an animal cell?
(b) Does it represent a prokaryotic cell or a eukaryotic cell?

Difference between zoo and wildlife sanctuary

Discuss the effects of deforestation on Environment

Discuss the effects of deforestation on Earth

Some tribals depend on the jungle. How?

What are the causes and consequences of deforestation? 

Compare LPG and wood as fuels.

Give reasons.
(a) Water is not used to control fires involving electrical equipments.
(b) LPG is a better domestic fuel than wood.
(c) Paper by itself catches fire easily, whereas a piece of paper wrapped around an aluminium pipe does not.

Name the unit in which the calorific value of a fuel is expressed.

Explain how CO₂ is able to control fires.

Can the process of rusting be called combustion? Discuss.

Give reasons for the following:
(a) Aluminium foils are used to wrap food items.
(b) Immersion rods for heating liquids are made up of metallic substances.
(c) Copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are stored in kerosene.

What happens when
(a) dilute sulphuric acid is poured on a copper plate?
(b) iron nails are placed in copper sulphate solution?
Write word equations of the reactions involved.

Explain why copper vessel acquires a dull green coating.

The doctor reported iron deficiency in the body. Where is iron present in our body?

Explain why zinc metal can displace copper from copper sulphate solution but copper cannot displace zinc from zinc sulphate solution

Give examples to show that plastics are noncorrosive in nature.

Why is rayon called an artificial silk?

What are the properties of nylon?

Write the difference between the raw materials used in rayon and other synthetic fibres like nylon or polyester.

What are the disadvantages of synthetic fibres?

Draw structure of virus and amoeba.

How can we prevent the following diseases?
(a) Cholera (b) Typhoid (c) Hepatitis-A

Give causative microorganism, mode of transmission and one preventive measure Qf human diseases like Polio, Cholera and Hepatitis-B.

During biology class, teacher was telling about microbes and how they are useful to humans. Hearing this, Jasmine got confused as she knew the TB caused to her uncle is due to a microbe. She asked his teacher about it. The teacher appreciated her for question and explained the whole class.
(a) What are microbes?
(b) How are microbes helpful to humans?
(c) Name one microbe
(i) used in household products.
(ii) used in antibiotics.
(d) Mention two diseases other than TB caused by microbes.
(e) Identify the values shown by Jasmine.

Write a short paragraph on the diseases caused by micro-organisms.

Paddy is a major cereal crop in our country.
(a) In which season is paddy cultivated?
(b) Discuss the method of sowing.
(c) What measures must be taken to prevent spoilage and insect attack of harvested grains?

As a part of eco-club activity, students were asked to raise a kitchen garden in the school premises. They were provided with some materials given in the box. List the other materials you would require. How will you plan the garden? Write the steps. Khurpi, water-can, spade, shovel

Explain various agricultural practices in sequential manner.

What is irrigation? Describe two methods of irrigation which conserve water.

Discuss various systems of irrigation.

What are the advantages of using CNG and LPG as fuels?

Name the petroleum product used for surfacing of roads.

Describe how coal is formed from dead vegetation. What is this process called?

Explain why fossil fuels are exhaustible natural resources.

Sunlight and air are inexhaustible natural resources. Comment.

Some properties are listed in the following table. Distinguish between metals and non-metals on the basis of these properties.

Can you store lemon pickle in an aluminium utensil? Explain

What happens when
(a) dilute sulphuric acid is poured on a copper plate?
(b) iron nails are placed in copper sulphate solution?
Write word equations of the reactions involved.

Explain why copper vessel acquires a dull green coating.

What happens when samples of metals and non-metals react with acids?

Give examples which indicate that nylon fibres are very strong.

Explain why plastic containers are favoured for storing food?

Should the handle and bristles of a toothbrush be made of the same material? Explain your answer.

'Avoid plastics as far as possible'. Comment on this advise

Describe an activity to show that thermoplastic is a poor conductor of electricity

What are the major groups of microorganisms?

Write 10 lines on the usefulness of microorganisms in our lives.

Write a short paragraph on the harmful effects of microorganisms.

Microorganisms survive under adverse conditions. How?

What will happen to 'pooris' and 'unused kneaded flour' if they are left in the open for a day or two?

Write a paragraph in your own words on each of the following - Preparation of soil

Explain how soil gets affected by the continuous plantation of crops in a field.

What are weeds? How can we control them?

The levelling of ploughed field is beneficial. Give reasons to support your answer.

State two advantages of using chemical fertilisers over manures. What would happen if fertilisers are used in excess?

Name the chemicals which are used in refrigerators and air conditioner and damage ozone layer when released in air.

An alternative fuel for vehicles is CNG. Write its full form.

Name any two water pollutants which are toxic for both plants and animals

We need to filter water before drinking. Give reason.

A fuel can be used in vehicles in place of petrol and diesel. Name it.

Can we hear the sound on the moon?

In the picture of rotating earth given as figure mark the position of Pole star.

Can we read the distance of nearest star from the Earth conveniently?

Give the name of the periodic comet. Why is it called so?

Paheli saw the moon through a glass window at 8:00 PM. She marked the position of the moon on the glass pane. She got up at 4 AM in the morning. Will the moon be visible at the same position?

Mention for how much duration, image stays on retina.

Why are we able to see the tap water in the glass even though it is colourless?

Black objects appear black. Why?

White light is a combination of which colours?

A banana appears yellow. Why?

What are the interactions of these two types of charges with one another?

If a charged plastic straw is brought near another uncharged plastic straw, what will happen?

Mention the name of the natural phenomena which can be predicted to some extent.

Give the name of the scale that is used to express the power of an earthquake.

If a charged plastic straw is brought near another uncharged plastic straw, then what actually happens?

It is dangerous to touch an electrical appliance with wet hands. Explain why

Explain, why is a layer of zinc coated over iron.

Since, when an electric current is passed through two solutions A and B, the bulb glows brightly for solution B and dimly for solution A. So, which of the two is a better conductor?

Mention the name of three liquids which can conduct electricity

The fresh fruits and vegetables conduct electricity to some extent. Explain why.

Give an ill effect of noise pollution

A hearing aid that is attached to the ear helps people who suffer from hearing loss. What is the main function of the hearing aid?

What is the name of the strings which vibrates and voice box when we talk?

What is the difference between pitch and frequency?

What is ultrasound?

Give a reason for calling friction as a necessary evil.

Mention the moment when the rolling friction comes into play.

If a body is moving on rough horizontal surface towards east, then in which direction the frictional force will act?

Why an arrow with a pointed tip can move faster in air than that with a flat tip?

Is the friction same for all the surfaces?

A girl is pushing a box towards East direction. In which direction should her friend push the box so that it moves faster in the same direction?

Does the palm apply any force on the ball, when we place our palm in front of a moving ball?

Briefly mention the interaction of poles of two magnets.

While sieving grains, small pieces fall down. Which force pulls them down?

Briefly, describe the walking of camels on sand.

Name the female hormone produced by ovaries that helps in development of mammary glands.

In a village, a girl of 12 years was married to a boy of 24 years. Is this marriage legal?

A sex chromosome is responsible for determining the sex of the baby. Give its name.

Name the hormone which brings about metamorphosis in silk moth.

What is the common name of the bulge (or projection) at the front of throat in grown up boys?

Does the tail in a sperm serve a specific purpose? If yes, what is it?

An organism has both male and female reproductive organs. Is it possible? If yes, name such organism.

X is the reproductive cell produced in a woman's Y while Z is the reproductive cell that is produced in the testes of a man. What can X, Y and Z be?

A term is used for the 'bulges' observed on the sides of the body of Hydra. What is it?

Name the male sex hormone.

Amoeba keeps changing its shape. Is there any advantage of doing so by it?

Is there anything common among a bacteria and an elephant? If yes, what is it?

Certain kind of cells do not have a cell wall around them. What are they called as?

Have you heard of a cell that behaves like a complete organism? Give its name

What are the functions of cell wall in plant cells?

Can a forest regenerate naturally in a short period of time?

You heard about rock shelters in this chapter. What are these?

Name the plant found in Satpura forests

 How are even small animals important in an ecosystem?

Tiger is considered an endangered species. Give reason.

Name the substance which gives heat and light after combustion.

Which type of substances are called combustible substances?

What do you mean by deforestation?

Why should we take special care in storing kerosene oil?

What are the different zones of a candle flame?

What does CNG stand for and why is it considered to be a better fuel than petrol

Give two natural resources. Why these are called natural resources.

Where was the first oil well drilled in India?

Petroleum is called black gold. Why?

How can you define coke?

Name one metal and one non-metal which exist in liquid state at room temperature.

Which metal is stored in kerosene?

Name a non-metal which is kept in water

How can you say that metals have a property of sonorousness?

Name two major non-metals which are present in fertilisers and enhance the growth of plants.

Which synthetic fibre contains the organic group similar to those which give fruits their sweet smell?

Write the name of fibre which is the first fully synthetic fibre.

The manufacture of which artificial fibres contributes to deforestation?

As a responsible citizen, we should remember the 4R principle. Can you tell what do 4Rs stand for?

For making PVC pipes, which type of plastic (thermoplastic or thermosetting plastic) is used?

Yeast is used for commercial use. Write one commercial use of yeast.

Name the process in yeast that converts sugars into alcohol.

Which pathogen causes anthrax?

We are advised to avoid collection of water anywhere. Why?

Use a word for disease causing microorganisms

The rabi crops are known as winter crops. Give reason.

To overcome what problems, the modern methods of irrigation are used.

In agricultural practices, which of the following comes first: Harvesting or sowing?

Is there any advantage of using a cultivator?

Paddy cannot be grown in winter season. If yes, why?

Which of the following is nota greenhouse gas?

Which of these can cause acid rain ?

Which of the following is not a source of air pollution?

Which of the following will reach the earth in greater amounts if the amount of chlorofluorocarbons released into the air increases?

Highest percentage of air consists of

Which of the following is not a member of the solar system?

The change in seasons on the earth occurs because

Which star is nearest to the Earth?

Morning star is the name given to

What term is used for celestial bodies that revolve around the sun in highly elliptical orbit?

Angle of incidence is equal to the angle of reflection

As the angle between two plane mirrors is decreasing gradually, the number of images of an object placed between them

How does the eye change in order to focus on near or distant objects?

The change in converging power of an eye lensis caused by the action of

Which of the following statements is correct regarding rods and cones in the human eye?

An electroscope is a device which is used to find if an object is

The movement of the earth's plates causes

The earth's plate responsible for causing earthquake is

Where is the lightning rod attached to protect the building from lightning?

Major earthquakes are less likely to occur in

A tester is used to check the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows brightly for liquid A, while it glows very dimly for liquid B. You would conclude that

An electric current can produce

An electrolyte is

The solution that can conduct electricity is of

Which one of the following solutions will not conduct electricity

Sound can travel through

The hearing range of human ear is

The normal range of vocal cords in women is

Vibrations in a body produce

1 Hz is equal to

Alida runs her toy car on dry marble floor, wet marble floor, newspaper and towel spread on the floor. The force of friction acting on the car on different surfaces in increasing order will be

It is difficult to walk on a wall polished floor because friction between our feet and floor is

A toy car released with the same initial speed will travel farthest on

We can increase the friction by

If we apply oil on door hinges, the friction will

State of motion is described by

Force due to the charged particles is known as

Which one of the following forces is a contact force?

Force is due to

Some mustard oil is kept in the beaker. It will exert pressure

Adolescents should be careful about what they eat, because

The faulty functioning of an endocrine gland can make a person very short or very tall. This gland is

The beginning of menstruation at puberty is called

The most conspicuous visible change that occurs in boys during puberty is

AIDS can spread from an infected person to another person through

In human beings, the correct sequence of events during reproduction is

Which of the following is not a viviparous animal?

The multicellular organism which reproduces by budding is

Which is not oviparous animals?

Tadpole is the larva of

The structural and functional unit of life called cell was discovered by

Which one of the following terms is not a part of the nucleus?

Out of the following, which animal is unicellular?

A suitable term for the various components of cells is

Which of the following is not a plastid?

Wild buffalo is an endangered species because

Which one of the following statements is true about a biosphere reserve?

Deforestation increases the level of one of the following the atmosphere.

The Red Data Book keeps a record of all the
(i) endemic species
(ii) endangered plants
(iii) extinct species
(iv) endangered animals

Which statement is incorrect about endangered species?

Various materials which are obtained from nature are called natural resources. Which of the following is not a natural resource?

Air is a natural resource and cannot be exhausted by human activities. It is known as inexhaustible natural resource. Which of the following is another inexhaustible natural resource?

Which of the following is a pair of exhaustible natural resources?

Coal is formed from the remains of

Which substance is formed by the carbonisation of dead vegetation?

A substance which reacts with oxygen giving heat is called a combustible substance. Which one of the following is a combustible substance?

Which one of the following has the highest calorific value?

If a person's clothes catch fire. The best way to extinguish the fire is to

Choose the incorrect statement from the following. Forest fires are usually due to

The calorific value of a fuel is expressed in a unit called

Pick the synthetic fibre out of the following.

Which of the following is not a common property of plastics?

Which of the following is non-biodegradable?

The synthetic fibres are also known as ................fibres.

Peels of vegetables and fruits are......

Metals are generally hard. Which of the following metals is an exception and can be cut with a knife?

Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?

Which of the following non-metals reacts and catches fire on exposure to air?

...................foils are used to wrap food items

.................gas is liberated when metals react with acids.

Yeast is used in the production of

Alcohol is produced with the help of

The two microorganisms which live in symbiotic association in lichens are

______________ is a nitrogen fixing bacteria.

Carriers of specific microorganisms are called ___________________

Which of the following statements is not true for organic manure?

Planting of seeds is called

Which one of the following conditions is not essential to grow maize?

...................is a device to spread seeds in soil

A most common weedicide is..........

Adolescents should be careful about what they eat, because

Reproductive age in women starts when their

The faulty functioning of an endocrine gland can make a person very short or very tall. This gland is

The beginning of menstruation at puberty is called

Structure present in a cell which is responsible for determination of the sex of a baby is

In human beings, the correct sequence of events during reproduction is

In the list of animals given below, hen is the odd one out. Human being, cow, dog, hen. The reason for this is

Which of the following is not a part of the human male reproductive system?

Sets of reproductive terms are given below. Choose the set that has an incorrect combination.

Reproduction by budding takes place in

The structural and functional unit of life called cell was discovered by

Identify the correct statement about cells.

Which one of the following terms is not a part of the nucleus?

The jelly-like fluid substance present in cells is called

Read the following terms and select the pair that is related to inheritance of characters

Wild buffalo is an endangered species because

Which one of the following statements is true about a biosphere reserve?

Deforestation increases the level of one of the following the atmosphere.

Which one of the following statements is true about endemic species?

In our country, large patches of forests are being cleared for cultivation of crops. The environmental impact of such a practice will lead to :

A substance which reacts with oxygen giving heat is called a combustible substance. Which one of the following is a combustible substance?

On placing an inverted tumbler over a burning candle. the flame extinguishes after sometime. This is because of non-availability of

If a person's clothes catch fire. The best way to extinguish the fire is to

The substance expected to have the highest ignition temperature out of the following is

Choose the incorrect statement from the following: A good fuel is one which:

Various materials which are obtained from nature are called natural resources. Which of the following is not a natural resource?

Air is a natural resource and cannot be exhausted by human activities. It is known as inexhaustible natural resource. Which of the following is another inexhaustible natural resource?

The World's first oil well was drilled in :

It was used for street lighting for the first time in London.

Coal-tar contains about _______ substances:

Which of the following statements is correct?

Which of the following is not a metal?

The substance that will be flattened on beating with a hammer is

Metals are generally hard. Which of the following metals is an exception and can be cut with a knife?

Metals can be cut with a knife:

Pick the synthetic fibre out of the following.

Which of the following is a source of rayon?

Polycot is obtained by mixing

The most suitable material for the preparation of handles of cooking utensils is

Which of the following is not a common property of plastics?

Yeast is used in the production of

Carrier of malaria-causing protozoan is

Alcohol is produced with the help of

The disease caused by a protozoan and spread by an insect is

Pathogenic microorganisms present in host cells are killed by medicines called