The graph given below shows the distribution of the major biomes of the world.

Answer the following questions based on the graph.
(a) Identify the biomes A, D, E, F.
(b) Which of the biomes shows the maximum range of
(i) Mean annual precipitation
(ii) Mean annual temperature?

The graph given below depicts the organismic response to changing external environmental conditions. According to their response, the organisms are grouped into two types.

Answer the following questions.
(a) Name the group of organisms, which will show pattern A. Give an example.
(b) ame the group of organisms, which will show pattern B. Give an example.
(c) Define homeostasis.

Study the three representative figures of age pyramids relating to human population and answer the questions that follow:

(a) Wrrte'the names given to the three kinds of age pyramids, (I), (il) and (iil).
(b) Give reason for each, why you have named them so.

'The population of a metro city experiences fluctuations in its population density over a period of time'.
(a) When does the population in a metro city tend to increase?
(b) When does the population in a metro city tend to decline?
(c) If 'N' is the population density at the time 't', write the population density at the time 't + l'.(Delhi 2020).

(I) Which of the above process(es) represent(s) an increase in population?
(ii) Which ofthe above process(es) represent(s) a decrease in population?
(iii) If a new habitat is just being colonised, out of the four process(es) affecting the population growth, which one contributes the most?

If in a population of size 'N', the birth rate is represented as 'b' and the death rate as 'd', the increase or decrease in 'N' during a unit time period 't' will be
dN/dt = (b - d) x N
The equation given above can also be represented as
dN/dt = r x N, where r = (b - d).
(a) What does 'r' represent in the above?
(b) Write anyone significance of calculating 'r' for any population.
(c) In a pond there are 100 frogs. 20 more were born in a year. Calculate the birth rate of this population.

Study the population growth curves shown in the graph and answer the following questions.
(i) Identify the growth curves 'a' and 'b'.
(ii) Which one of them is considered more realistic and why?
(iii) What does the dotted line in the graph indicate?

There is no natural habitat on earth, which is occupied by a single species. In nature, plants, animals and microbes do not and cannot live in isolation. Interspecific interactions arise from the interaction of populations of two different species.
(a) Even a plant species, which makes its own food cannot live alone. Give two examples, where plants depend on other species for survival.
(b) Name the type of interspecific interaction seen in each of the following examples.
(i) Disappearance of smaller barnacles when Balanus dominated intertidal area of the sea coasts of Scotland.
(ii) Clown fish living among the stinging tentacles of sea anemone.
(iii) The Wasp species pollinating a fig inflorescence.
(iv) Cuscuta growing on hedge plants.

Study the table given below and answer the questions that follow:

(+ = Beneficial interaction)
(- = Detrimental interaction)
(0 = Neutral interaction)
(i) Identify the type of interaction (a), (b), (c) and (d).
(ii) Why are predators 'prudent' in nature?

It is generally believed that competition occurs only when closely related species compete for the same resources that are limiting.
Give two examples to show that the above statement is not always true.

Read the following and answer the questions given below:
Unlike animals, plants cannot runaway for their defence, so, they have evolved on surprising variety of morphological and chemical defence against the herbivores. Thorns are the most common physical means of defence. Many plants secrete and store chemicals that make herbivore sick when they are eaten, inhibit feeding or digestion, disrupt its reproduction or even kill it. Some plants produce highly poisonous chemicals and that is why no cattle or goats browse on those plants. A large variety of chemical substances that we extract from plants on a commercial scale are produced by them actually as defence against grazer and browser.
(i) Why we never see cattle or goats browsing on weed Calotropis?

(ii) Which of the following is most likely to sick by consuming chemicals produced by plants?

(iii) Plant evolve different morphological and chemical defences against

(iv) Assertion: Some plant functions as predator in nature.
Reason: Phytophagous insects feed on plant sap.
(a) Both A and Rare true and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) Both A and R are false

Read the following and answer any four questions from (i) to (v) given below:
Kangaroo rat seldom drinks water. It has thick coat to minimise evaporative desiccation. The animal seldom comes out of its comparatively humid and cool burrow during the day time. 90% of its water requirement is met from metabolic water (water produced by respiratory breakdown of fats) while 10% is obtained from its food. Loss of water is minimised by producing nearly solid urine and faeces. As the animal faces acute water scarcity, it develops two types of adaptations: reducing water loss and ability to tolerate desert conditions.
(i) Kangaroo rat is a

(ii) Metabolic water refers to

(iii) Desert animals minimise water loss by

(iv) Assertion : Kangaroo rat can tolerate and thrive in wide temperature range and is known as stenothermal.
Reason: Kangaroo rats go into hibernation during winter to escape cold weather.

(v) The adaptations in an organism are meant for

Read the following and answer any four questions from (i) to (v) given below:
Organism P has thick lips and tongue so that it can easily feed on the commonly available spiny plants. Organism Q has thick layer of insulating fat under the skin. It was strong hooves to walk steadily on steep surfaces and lives in burrows during winters. Organism R has bright colours and sticky pads on its fingers and toes. It lives on trees.
(i) Which of the following is correct habitat for organisms P regarding its adaptation?

(ii) Which of the following is correct match regarding organism Q and its habitat?

(iii) Which of the following is incorrect regarding organisms R's habitat?

(iv) The dominant plants in habitat where P lives could be

(v) Organisms P,Q and R respectively most likely occur in

Read the following and answer any four questions from (i) to (v) given below:
During teaching about various environmental factors, a teacher draw a figure that depicts like history strategies for three plant species (X, Y and Z) along 3 axes - strength of competition with other organisms, level of disturbance in the habitat and level of environmental stress in the habitat. Species X grows in habitats where competition among species is high but disturbance and stress are low. Species Y grows in habitats with high environmental stress but with low intraspecies competition. Species Z grows in highly disturbed habitats with low environmental stress.

(i) Which of the following is correct regarding plant type X?

(ii) Environmental stress occurs through

(iii) Select the correct option regarding plant type X, Y and Z.

(iv) Y type of plants grow under high stress and

(v) Assertion: Plant growth rate is high in area of high stress and high disturbance.
Reason: High stress and high disturbance promote breeding capacity in plants.

Read the following and answer any four questions from (i) to (v) given below:
Regular change in temperature that occurs at specific intervals of time is called thermoperiodicity. It is of two types-diurnal and seasonal thermoperiodicity. Diurnal periodicity refers to temperatures of day and night. It determines periods of annual activity. In season periodicity different temperature prevails in different seasons of the year. They favour different aspects of plant and animal life termed as phenology. For example in wheat, leaf growth requires a temperature of 10°-25° C. Apple requires temperature below 7°C for a period of 800 hrs before flowering and fruiting can occur. Low temperature is required for germination of some seeds as well as flowering in some plants. It also determines growth, reproduction, colour and morphology of animals. Both low and high temperature cause stress in organisms which is overcome by particular adaptations.
(i) Some plants require low temperature treatment for flowering. This phenomenon is known as

(ii) Animals found in arctic zones are called

(iii) Which of the following parts of wheat plant grows maximum in temperature around 10°-25°C ?

(iv) "Different temperatures prevail in different seasons of the year:' It represents

(v) Assertion: Low and high temperature causes stress in organisms.
Reasons: Organisms show specific adaptations to overcome stressful condition.