Final answer:
Plants do not excrete anything at night in the dark. Instead, they undergo respiration, taking in oxygen and releasing carbon dioxide. They do not produce oxygen without sunlight.
Step-by-step explanation:
Plants do not excrete anything during the night in the dark. Instead, they undergo a process called respiration, where they take in oxygen and release carbon dioxide. This is similar to how animals breathe.
During respiration, plants break down glucose and release energy. However, since there is no sunlight available for photosynthesis, plants do not produce oxygen at night.