Although potato tuber is an underground plant part, it is considered as a stem. Give two reasons.

3

(a)

In an experiment, Mr. Jhon dissected a large potato tuber into serval small pieces and then placed each piece in a separate pot for germination. After few days, he observed that a few pieces germinated and developed new plants. The others did not germinate at all. Give the possible reasons.

3

(a)

A gardener grafted a scion of "Dashahari" mango twig to the stock of Zea mays. He took all precautions during the grafting process but failed to get positive results as the grafting was not successful. Give the possible reason.

3

(a)

Select out any four animals to demonstrate examples of bisexual organism:
Frog, Earthworm, Cockroach, Spider, Sponge, tapeworm, leech, honey, bee, Rat, Rabbit, House fly.

3

(a)

Ramesh tried to propagate sugarcane vegetatively by sowing a segment of stem having internodal region only. Suresh tried the same by sowing a segment having an internode. Who chose the correct segment and why?

3

(a)

In the following figures label the parts responsible for production of new plants

3

(a)

Which one is advance- external fertilization or internal fertilization? Give reasons in support of your answer.

3

(a)

What will you do to convert a bisexual flower into a female flower so that it is cross-pollinated artificially by the pollens of some other plant?

3

(a)

In angiosperms, the pollen germinates to produce pollen tube that carries two gametes.What is the purpose if carrying two gametes when single gamete can fertilize the egg?

3

(a)

It is observed that gametes of both haploid and diploid parents are haploid thousand times the number of female gametes. What is the reason behind it?

3

(a)