AP BIOLOGY

Detailed explanation-1: -Excretion of gaseous waste in plants takes place through stomatal pores on leaves. Oxygen released during photosynthesis is used for respiration while carbon dioxide released during respiration is used for photosynthesis.

Detailed explanation-2: -Plants remove carbon dioxide and oxygen by vapour through the stomata, this process is called transpiration. Thus waste gaseous products or plants are carbon dioxide and oxygen.

Detailed explanation-3: -In terms of transpiration, or plant water use, an increase in atmospheric CO2 means that stomata, or the pores on leaves that exchange gases between the leaf and the atmosphere, do not need to open as much. This means that, at the scale of a leaf, less water is lost and there is lower transpiration.

Detailed explanation-4: -Transpiration is the evaporation of water from plants occurring at the leaves while their stomata are open for the passage of CO2 and O2 during photosynthesis.

Detailed explanation-5: -Stomata consist of microscopic pores, each flanked by a pair of guard cells. Guard cells can increase or decrease the size of the pore via changes in their turgor status, hence regulating both CO2 entry into the leaf and transpiration, or the loss of water from the leaf.