the correct answer is - plants use oxygen and release carbon dioxide into the atmosphere.
the plants have multiple process going on when it comes to their growth and development, and one of those processes is the respiration. the respiration, in essence, is the process in which the plants are using the sugars previously made with the process of photosynthesis, combining them with oxygen, thus producing energy for their growth.
as mentioned, the plants use oxygen in this process, and they get through their leafs and through their roots, while in the same time, they are releasing carbon dioxide through their leafs and roots.
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