Unisexuality of flowers prevents

(1) autogamy, but not geitonogamy

(2) Both geitonogamy and xenogamy

(3) geitonogamy, but not xenogammy

(4) autogamy and geitonogamy

What does the filiform apparatus do at the entrance into ovule?

1. It helps in the entry of pollen tube into a synergid

2. It prevents entry of more than one pollen tube into the embryo sac

3. It brings about opening of the pollen tube

4. It guides pollen tube from a synergid to egg

Which one of the following is resistant to enzyme action?

(1) Cork

(2) Wood fibre

(3) Pollen exine

(4) Leaf cuticle

Male gametes in angiosperms are formed by the division of:

(1) microspore

(2) generative cell

(3) vegetative cell

(4) microspore mother cell

Parthenocarpic tomato fruits can be produced by :

(1) removing androecium of flowers before pollen grains are released

(2) treating the plants with low concentrations of gibberellic acid and auxins

(3) raising the plants from vernalized seeds

(4) treating the plants with phenylmercuric acetate.

Long filamentous threads protruding at the end of a young cob of maize are :

In angiosperms, microsporogenesis and megasporogenesis

(1) occur in anther

(2) form gametes without further divisions

(3) involve meiosis

(4) occur in ovule

Coconut water from a tender coconut is

1. Immature embryo

2. Free nuclear endosperm

3. Innermost layers of the seed coat

4. degenerated nucellus

Which of of the following fruits is parthenocarpic?

1. Brinjal

2. Apple

3. Jackfruit

4. Banana

Male gametophyte in angiosperms produces 

1. two sperms and a vegetative cell

2. single sperm and a vegetative cell

3. single sperm and two vegetative cells

4. three sperms