When the pollen tube enters the ovule through the integuments,the process is called:

How many of the following statements are true about the figure given below?
i. Germination of pollen grain.
ii. Motile male gametes.
iii. Two male gametes and one female gamete.
iv. Pollen grain without exine.
v. Tube nucleus at the tip of pollen tube.

Pollen tube discharges its gametes in

Mention the viability of pollen grains.

Intra-species incompatibility can be overcome by

In . . . . . . pollen grains cause allergy.