AP BIOLOGY

Detailed explanation-1: -Higher than ambient CO2 concentrations mediate a closure of stomatal pores in plants and conversely, low CO2 concentrations trigger opening of stomatal pores.

Detailed explanation-2: -Plants ‘breathe’ too, but they do it through tiny openings in leaves called stomata (singular: stoma). Stomata open and close to allow the intake of carbon dioxide and the release of oxygen.

Detailed explanation-3: -The correct option is A True. During photosynthesis, Carbon dioxide(CO2) gas is taken in through stomata from the atmosphere. Oxygen(O2) gas is released through stomata into the atmosphere as a by-product.

Detailed explanation-4: -Crop plants have among the largest reductions in stomatal conductance at elevated [CO2]. The relative reduction in stomatal conductance caused by a given increase in [CO2] is often not constant within a day nor between days, but may vary considerably with light, temperature and humidity.