Plants perform photosynthesis and respiration. Dead plants are broken down and become part of the soil. Which of the following m
atter do plants help to cycle through ecosystems? Select one: a. carbon only
b. carbon, oxygen, and nitrogen only
c. carbon and oxygen only d. carbon, oxygen, nitrogen, and water
If you are allowing plants to decompose when dead that will add nitrogen to the ecosystem. Plants need nitrogen for photosynthesis. Decomposition and carbon dioxide provide carbon. They expel oxygen. I would say they provide all between dying (decomposition) and respiration.
