Wei Zi ecological paper

As can be seen from the figure, ① indicates the respiration of plants, which decomposes organic matter into carbon dioxide and water and discharges it into the atmosphere; ② indicates photosynthesis of plants, which synthesizes carbon dioxide and water in the environment into organic matter and releases oxygen; ④ indicates the breathing of animals; ③ indicates the decomposition of microorganisms, which decomposes animal and plant remains into carbon dioxide and water and discharges them into the atmosphere.

A, the composition of the "atmosphere" in the picture is oxygen and carbon dioxide, so it does not meet the meaning of the question;

B the direction of energy flow in the illustrated ecosystem is from plants to animals, from animals to microorganisms, and from plants to microorganisms, which does not meet the meaning of the question.

C, physiological processes ① ③ ④ all indicate the respiration of living things, ② indicate the photosynthesis of plants, so it doesn't meet the question;

D. Photosynthesis is a process in which green plants use light energy to synthesize organic matter from carbon dioxide and water in chloroplasts, release oxygen, and at the same time convert light energy into chemical energy and store it in the synthesized organic matter. The significance of photosynthesis is not only to provide matter and energy for living things, but also to maintain the balance of carbon and oxygen in the biosphere, so it meets the question.

So choose D.