Pollen grains are shed at which stage?

1. 2 celled 

2. 3 celled

3. Usually at 2-celled, but sometimes 3-celled

4. Single celled stage

False fruit in an apple is formed from

1. sepals

2. thalamus

3. peduncle

4. petals.

Seed of castor is

1. non-endospermic, exalbuminous

2. endospermic albuminous

3. endospermic exalbuminous

4. non-endospermic albuminous.

During formation of which of the following free nuclear division occurs?

1. Flower

2. Endosperm

3. Gametes

4. Fruit

Pollen grains are able to withstand extremes of temperature and dessication because their exine is composed of

1. cutin

2. suberin

3. sporopollenin

4. callose

The pollen tube usually enters the embryo sac

1. through one of the synergids

2. by directly penetrating the egg

3. between one synergid and central cell

4. by knocking off the antipodal cells

Double fertilization involves

1. fertilization of the egg by two male gametes

2. fertilization of two eggs in the same embryo sac by two sperms brought by one pollen tube

3. fertilization of the egg and the central cell by two sperms brought by different pollen tubes

4. fertilization of the egg and the central cell by two sperms brought by the same pollen tube.

What is the charasteristic of tapetum ?

1. It does not store food.

2. It is multi-nucleated.

3. It is multi-layered structure.

4. It nourishes the megaspore.

The pollen grains of rice and wheat lose their viability in ___ minutes of their release.

1. 30

2. 10

3. 60

4. 90

After double fertilizaton, a mature ovule has

1. 1 diploid and 1 haploid cell

2. 1 diploid and 1 triploid cell

3. 2 haploid and 1 triploid cell

4. 1 haploid and 1 triploid cell