A difference between plant cells and animal cells is that most animal cells are round whereas most plant cells are rectangular. Another difference would be that plant cells have a rigid cell wall that surrounds the cell membrane, animal cells do not have a cell wall.
A similarity is that both plant and animal cells have a nucleus.
I think the answer would be c. because for birds with longer beaks, it was easier to eat seeds off a cactus (for example), and for birds with shorter seeds, it was easier to eat seeds off the ground.
