Final answer:
Hot and dry conditions favor photorespiration in plants because when stomata are closed to conserve water, the enzyme Rubisco catalyzes "O₂ fixation" instead of fixing CO₂, leading to a decrease in photosynthetic efficiency.
Step-by-step explanation:
Hot and dry conditions favor photorespiration in plants because in these conditions, plants close their stomata to conserve water. When stomata are closed, CO₂ cannot enter the leaves and O₂ cannot leave, leading to a decrease in CO₂ levels and an increase in O₂ levels. As a result, the enzyme Rubisco, which is involved in the Calvin Cycle of photosynthesis, starts catalyzing a process called "O₂ fixation" instead of fixing CO₂. This process produces undesirable byproducts and leads to a decrease in photosynthetic efficiency. Hot and dry conditions exacerbate this process, making photorespiration more prevalent.