Question

If photosynthesis and cellular respiration form a cycle, why do plants need to continually take in carbon dioxide, oxygen, and water from the environment?

Answer 1

the light energy is stored in chemical energy, while this energy is utilised in respiration.

Answer 2

Plants release excess oxygen, carbon dioxide, and water back into the environment. They don’t store them indefinitely. So, they continually need to take in these elements.