In the process of photosynthesis, not only organic matter is formed, but also free oxygen. Its release into the environment can be seen in the following experiment.
Take two glasses filled with water. We put the shoots of the aquatic plant Elodea in the water with the slices up, cover them with funnels, on which we put test tubes. Now we will put the first glass in a dark cabinet, and the second in a bright light. In the light, in the second glass, Elodea emits gas bubbles.
We carefully remove the second test tube, filled with gas, closing its hole with your finger. Let’s put a smoldering torch into the test tubes. It lights up with a bright flame. This means that oxygen has appeared in this test tube (only this gas supports combustion). The same experiment carried out with a test tube from a dark cabinet shows that the torch is damping (i.e., there is no oxygen in the test tube).
Conclusion: green plants release oxygen only in the light.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.