Question

multiple choice question
stomata in the epidermis of the leaf ______.

• expand and contract the leaf surface to regulate temperature
• shuttle products of the light - dependent reactions to the light - independent reactions
• allow gases to enter and exit the leaf
• allow the passage of light into and out of the leaf

Explanation:

• Option 1: Stomata don't expand/contract the leaf surface for temperature regulation; guard cells control stomata opening/closing.
• Option 2: The shuttle of light - dependent to light - independent reaction products (like ATP and NADPH) occurs within the chloroplast, not via stomata.
• Option 3: Stomata are pores surrounded by guard cells. They open to let in $CO_2$ (needed for photosynthesis) and let out $O_2$ (a photosynthesis by - product) and water vapor (during transpiration), so they allow gas exchange.
• Option 4: Light enters the leaf through the cuticle and epidermal cells, not stomata. Stomata are for gas, not light, passage.

Answer:

C. allow gases to enter and exit the leaf