Desertification is caused by  A. human activity
B. leaching of the soil
C. solar heating patterns
D. temperature variations

oak trees? ? what was listed

burning fossil fouls really decrease the carbon in the atmosphere so b

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.