Answer:
Transportation of substances in cells, where they travel against the concentration gradient. However, it requires ATP to do so.
Explanation:
Answer:
Layer A is the crust and Layer B is the mantle.
Answer: Nutrition
Explanation: Nutrients are the essential nourishments for growth and the maintenance of life.
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.
