When seeds are attached to parent plant the type of germination is known as

Which one of the following pollinations is autogamous?

Which layer develops first during embryonic development?

Given below are four methods (A-D) and their modes of action (i) - (iv) in achieving contraception. Select their correct matching from the four options that follow

Mendel's Law of independent assortment holds good for genes situated on the :

Initiator (starting) codon in eukaryotes is

What is common to whale, seal and shark?

Tobacco consumption is known to stimulate secretion of adrenaline and nor-adrenaline. The component causing this could be:

Which one of the following products is used in cosmetics and polishes.

An organism used as a biofertilizer for raising soyabean crop is

Given below is a sample of a portion of DNA strand giving the base sequence on the opposite strands. What is to special shown in it?
5'.........GAATTC.....3'
3'.........CTTAAG.....5'

Amplification of gene of interest by using DNA polymerase may go upto

In which one of the following habitats does the diurnal temperature of soil surface vary most?

Select the formula for ecological efficiency

Which one of the following pairs of gases are the major cause of 'green house effect'?

If the Bengal tiger becomes extinct

List the changes observed in an angiosperm flower subsequent to pollination and fertilization.

Describe the structure of typical microspore (Pollen grain).

What is foetal ejection reflex? Explain how it leads to parturition?

Why are Copper-containing intrauterire devices considered an ideal contraceptive for human females?

A man with blood group A married a woman with B group.They have a son with AB group and a daughter with blood group O.Work out and show the possibiliy of such inheritance

Draw a schematic diagram of a part of double-stranded dinucleotide DNA chain, having all the four nitrogenous bases and showing the correct polarity

How was the earth's atmosphere formed?

Briefly, explain the various types of disorders arising from improper function of the immune system

Discuss pasturage/crop/flora of honey bee.

What is brewing?

(a)Explain how to find whether an E.Coli bacterium has transformed or not when a recombinant DNA bearing ampicillin-resistant gene is transferred into it.
(b)What does the ampicillin-resistant gene act as, in the above case?

Mention two adaptations the mammals of colder regions have, to minimise the loss of body heat.

A part from plants and animals,microbes form a permanent biotic component in an ecosystem.While plants have been referred to as autorophs and animals a sheterotrophs,How do microbes fulfil their energy requirements?

What are the 2 types of source of water pollution?

Discuss briefly the ultraviolet B

Match the items in Column (A) with Column (B). Each point in column (A) has minimum one match in column (B) and maximum two matches.

Draw a diagram of human sperm. Label only those parts along with their functions that assist the sperm to reach and gain entry into the female gamete.

'Introducing sex education in schools is a good step for providing the right information to adolescents'. In context to the statement given above, answer the questions that follow:
(i) Which part of the brain controls the sex urge?
(ii) what are the necessary topics that should be taught in schools, in the context of STD_s and AIDS?
(iii) What do you understand by the term emotional brain?

How is aneuplody different from polyplodiy?  Mention their causes.

Describe Griffith's experiment to demonstrate that DNA is the basic genetic material. What was an explanation for Griffith's observation given by Avery, McCarty and MacCleod?

What are the periods in Palaeozoic era and name the plant group that appeared in each of them,

Name the cells HIV attacks first when it gains entry into a human body.How does this virus replicate further to cause immunodeficiency in the body?

State the disadvantages of inbreeding among cattle. How it can be overcome?

Name any three organic acids and the bacteria that produce them.

Mention three uses of PCR.

How did an American Company, Elr Lily use the knowledge of r-DNA technology to produce human insulin?

Study the graph  given below:

(i) What does the curve 'a' represent in the graph? What does 'K' stand for?
(ii) Which one of the two curves is considered a more realistic one for most of the animal population?
(iii) Which curve would deplict the population of a species of deer if there are no predators in the habitat? Why is it so?

Represent schematically the decomposition cycle in a terrestrial ecosystem.

Narrowly utilitarian arguments are put forth in support of biodiversity conservation. Explain the other two arguments that are put forth in support of the same cause.

Co-extinction is the loss of species as a results of loss of other species that depends on it. Such effects are likely to be most severe in interactions. State the effect of such type of interaction on both species and an example of each.

(a) Name two animals showing external fertilisation.  Why are move gametes produced by such animals?
(b) Name two animals showing internal fertilisation.  What are the characteristics of the gametes produced by such aimals?

With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.

What is blastocoel in mammalian development? What does it signify from the point of view of phylogeny?

On world population day, Rohit and his friends arranged an awareness campaign on population explosion programme in their locality. Some elderly people tried to stop the children and asked them not to talk about such things in public.
The children convinced the elders about the need for the programme and on understanding their point of view, the elders also joined the campaign.
(i) Why is such awareness programme necessary?
(ii) What role has the government played in controlling population explosion?
(iii) When were reproductive health programmes initiated in India?
(iv) What values did Rohit and his friends show on the occasion?

Explain how a test cross can be conducted to distinguish between a homozygous and heterozygous dominant genotype.

In a maternity ward, two new born babies got exchanged and two women claiming to be the mother of one child and the matter went to the court.The judge asked to conduct DNA test of the child and two women, and on the basis of report settled the issue of paternity
Read the above passage and answer the following questions:
(i)What is the meaning of DNA test?
(ii)How is it helpful in deciding paternity issues?

Explain which of the following are homologous and which are analogous?
(a) Fish scales and bivalve (mollusc) shell
(b) Trunk of an elephant and hand of a chimpanzee
(c) Wing of a bat and wing of a bird
(d) Nails of a human being and claws of a cat
(e) Ginger and sweet potato.

Explain the different ways of diagnosing cancer.

Enumerate the points that have to be considered for successful bee-keeping.

Which type of food would contain lactic acid bacteria? Discuss their useful application.

(a) Mention the role of vectors in recombinant DNA technology. Give any two examples. (b) With the help of diagrammatic representation only, show the steps of recombinant DNA technology.

How is a transgenic tobacco plant protected against Meloidegyne incognitia?

(i) What is population density? Why are ecologists interested in measuring it?
(ii) Write the different ways of measuring population density. Explain any two with the help of specific examples.

In every summer, Ravi used to visit his native village. Many years ago when he was a small child, a large amount of soil was removed from his village land for construction purpose and as a result a pond was formed after rainy season. Every year, he observed gradual changes in the vegetation of the pond.
Read the above passage and answer the following questions:
(i) What is the term used to describe the process of colonization of a new barren area?
(iii) Define climax. What is the status of climax community?

How can you as individual, prevent the loss of biodiversity?

Why is ozone layer in stratosphere called a protective layer?