During which part of the day does photosynthesis primarily occur?

Photosynthesis primarily occurs during the day when sunlight is available. This process, performed by plants, algae, and some bacteria, relies on light energy to convert carbon dioxide and water into glucose and oxygen. The chlorophyll in plant cells captures sunlight, which is essential for the chemical reactions involved in photosynthesis. While some cellular respiration can occur at night, the light-dependent reactions of photosynthesis cannot take place without light, which is why the process is primarily confined to daylight hours.

In contrast, the other options suggest scenarios where photosynthesis would not occur effectively. For example, photosynthesis does not happen at night since there is no sunlight available. The idea that it occurs both day and night is misleading; instead, respiration can continue at night, but photosynthesis relies solely on daylight. The concept of it happening at sunrise and sunset implies it only occurs during these transition periods, which is also incorrect since it can occur throughout the day when sufficient light is present.