Q. What happens each day when the leaf of a plant is first exposed to light?

• (A) the epidermal cells on the upper surface of the leaf begin to photosynthesize
• (B) the cells of the spongy mesophyll begin to take up carbon dioxide, and are the only cells that are able to do so
• (C) the guard cells become more turgid and the stomatal apertures open
• (D) carbon dioxide diffuses out of the leaf