Answer:
D. Chemical - mechanical - thermal
Explanation:
D because the food is chemical and the mechanical is the human excersice, and it results in thermal
I believe it is A. Please forgive me if I am wrong.
They are part of the stomatal can be found in the skin of the leaf and stem. Guard cells have characteristic shapes can be bean-shaped or like sponge cake. They have thickened cell walls contain living protoplasm of chloroplasts (as opposed to skin cells)
