The picture shows the photosynthesis of green plants A and B.

A. The concept of photosynthesis is that green plants use light energy to convert carbon dioxide and water into organic matter (mainly starch) that stores energy, and release oxygen. Therefore, photosynthesis is completed through chloroplasts, which are the places of photosynthesis; The necessary condition of photosynthesis is light, so photosynthesis must have light to complete its process. A is correct and does not conform to the meaning of the question;

B, the water needed by green plants is absorbed from the soil through the root system, and the main area for root system to absorb water is the mature area of root tip.

C, through the concept of photosynthesis, we can see that green plants absorb carbon dioxide and release oxygen through photosynthesis, so ① stands for carbon dioxide, ② stands for oxygen, and C is wrong, which is consistent with the meaning of the question;

D through the concept of photosynthesis, we can see that green plants absorb carbon dioxide and release oxygen, which promotes the balance of carbon and oxygen in the biosphere. D is correct and does not meet the meaning of the question.

So: BC.