Final answer:
When stomata in a leaf close during the day, carbon dioxide levels decrease, oxygen levels increase, and C3 plants engage in photorespiration. The correct answer to the question is 'All choices but the halting of photosystems are correct.'
Step-by-step explanation:
When the stomata in a leaf close during the day, it causes multiple changes within the leaf's internal atmosphere. As stomata close to conserve water during times of drought and dry conditions, the concentration of carbon dioxide (CO2) within the leaf decreases because CO2 can no longer enter the leaf effectively. Conversely, because photosynthesis is slowed due to the lack of CO2, the concentration of oxygen (O2) within the leaf increases as it is less frequently being converted to CO2. This leads to C3 plants engaging in a process known as photorespiration, wherein O2 is used, and 3-phosphoglyceric acid (PGA) and CO2 are produced.
When the stomata in a leaf close during the day, the oxygen (O₂) levels would increase and the carbon dioxide (CO₂) levels would decrease.
Stomata are small openings on the underside of the leaf that allow the exchange of gases. They regulate the entry of carbon dioxide and the exit of oxygen. When stomata close, the exchange of gases is limited, leading to a decrease in carbon dioxide and an increase in oxygen levels.
For photosynthesis to occur, plants require carbon dioxide. When stomata close, the availability of carbon dioxide decreases, which affects the process of photosynthesis.
The correct answer to the question is E. 'All choices but the halting of photosystems are correct.' This is because while photosynthesis is slowed, it does not come to a complete halt, and photorespiration continues to occur.