Stems play an important role in a plant's life except for A. providing support for leaves, flowers, and fruit
B. defensive properties to protect a plant from infection and insects
C. increasing the amount of exposure it receives to sunlight
D. predicting the age of the plant

D. predicting the age of the plant

Explanation:

stems don't exactly have those powers. but they do give support by holding the plant upright. they do give defensive properties. and they do increase the amount of sun exposure (like with sunflowers). but they don't predict anything.

i believe it's c. the trait for large beaks will be passed on to future generations through natural selection.

since eventually smaller beaks would have to find another source of food or even eventually just die out from the lack of food.