Final answer:
The rate of photosynthesis initially increases with the intensity of light due to higher energy availability, but eventually plateaus when other factors limit the process. If a plant is exposed to red light specifically, the rate of photosynthesis can indeed increase, as red light is efficiently used in photosynthesis by chlorophyll.
Step-by-step explanation:
When the intensity of light is gradually increased from low to high, the rate of photosynthesis initially increases. This is because light provides the energy necessary for the process, and as light intensity increases, so does the energy available for the conversion of carbon dioxide and water into glucose and oxygen. However, beyond a certain point, further increases in light intensity do not increase the rate of photosynthesis, as other factors such as carbon dioxide concentration and temperature become limiting factors.
Specifically, this would apply to a plant being exposed to red light. Red light is one of the colors of light that is most effective for photosynthesis. If a plant is exposed solely to red light, the rate of photosynthesis can increase as red light photons are effectively absorbed by chlorophyll pigments used to drive photosynthesis.
Therefore, the correct response to the student's question would be: A increases.