1. Theoretically, plants could increase or decrease the size of individual stomata and still achieve the same result as varying the number of stomata. But they dont do this- plants only vary stomata number, not size. Why?

2. How many stomata would you expect desert plants to have relative to rain forest plants? When and for how long would these plants keep their stomata open?

3.Human activities in the past century have greatly increased the concentration of CO2 in the atmosphere. How will increasing CO2 levels affect stomata density and rate of opening/ closing? Can you think of any additional benefits to or problems for plants associated with stomata?