Pollen grains develop in which structure?
the anther
the stigma
the filament
the carpel

Pollen grains develop in the stigma.

Explanation:

In botany, the part of the gynecium that receives pollen during pollination is called stigma.

They are regions on the outer side of the surface of the carpels (the female leaves of the flower), separated from the ovary by style. Its surface is generally papillose, where each papilla is a cell, and moist, two features that facilitate the adherence of pollen. Once in the stigma, the pollen germinates, opening and growing from it a pollen tube through which the nucleus or nuclei that carry out the fertilization of the female gametes move. The tube must penetrate through the stigma and style tissue.

the answer is b.) hydrogen bonds between bases.