Question

define pollen grains and structure of pollen grains label it​

Answer 1

Explanation:

The pollen grain is the male gametophyte which contains the male gametes. The pollen grain is surrounded by two layers as exine which forms the outer layer and intine which forms the inner layer. The generative cell divides to form the two male gametes. The vegetative cell is responsible for the providing nutrition.

Answer 2

The stamen is the androecium composed of anther and filament. The anther contains pollen sacs which produce pollen grains. The pollen grain is the male gametophyte which contains the male gametes. The pollen grain is surrounded by two layers as exine which forms the outer layer and intine which forms the inner layer.