Answer:

28.

A

because

The enlarged portion at the top of the stamen is the anther. Inside the anther are pollen sacs, which produce pollen grains. When the pollen grains mature, the pollen sacs split open, releasing the dust like pollen grains.

29.

D

because

Flowers. Sexual reproduction is the sole function of flowers, often the showiest part of a plant. Flowers' beauty and fragrance evolved not to please humans but to attract pollinators (insects or birds), which are central to the reproductive process

30.

B

because

Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the corolla.