Pollen grains develop in which structure?

a. the anther

b. the stigma

c. the filament

d. the carpel

The flower is the reproductive organ of an angiosperm plant. The flower is made up of the calyx, corolla, stamen, and carpel. The stamen and carpel are directly involved in the development of gametes and zygote, while the calyx and corolla are the accessory parts of the flower.

• The stigma is a part of the female reproductive part, carpel where the pollen grains are received during fertilization.
• The filament is the part of stamen that supports the anther and is not directly involved in the pollen production.
• The carpel is the female reproductive part of the flower which produces the female egg cell, ovule.

Anther is where the pollen is produced and developed. Filament keeps the anther in place. Anther and the filament together forms the stamen. Anther is a separate pollen-producing unit from the rest of the flower. Pollen is a fine powdery particle produced by flowering plants that contains the male gamete of the flower.

The male sex cells of flowering plants are thus enclosed in tight capsules known as pollen and the correct answer is (a) pollen.