Which of the following conditions can affect the rate of photosynthesis?

The rate of photosynthesis is influenced by several factors, including light intensity, temperature, and the availability of water and carbon dioxide. Light intensity is critical because it provides the energy needed for the photosynthetic process. When light levels are too low, photosynthesis slows down, while very high light levels can also cause damage to the plant's tissues.

Temperature plays an essential role in photosynthesis because it affects the enzymatic reactions involved in the process. Each enzyme has an optimal temperature range, and deviations from this range can slow the reaction rates. For instance, at very low temperatures, the enzymes may become less effective, while excessively high temperatures can denature enzymes and halt photosynthesis altogether.

In addition, water availability is crucial, as it is not only a raw material for photosynthesis but also influences the plant's ability to maintain turgor pressure, which is necessary for overall plant health. Similarly, carbon dioxide concentration is vital as it is one of the key inputs in the photosynthetic process.

Therefore, the choice highlighting both light intensity and temperature accurately reflects key factors affecting the rate of photosynthesis, making it the correct answer.