The plants are living organisms that are producers. They are able to perform the process of photosynthesis. Through this process, the plants are included in numerous natural cycles, such as the oxygen cycle, carbon cycle, nitrogen cycle, water cycle. By using all these gases and the water, the plants manage to balance the atmosphere's composition and keep it healthy and in good condition that enables the other organisms to live. Basically, the plants are taking in the water in these gases for the process of photosynthesis, thus to produce their own food. As they use them, they release some of them in the atmosphere, some in the soil, while some are stored in them. The oxygen and the water vapor are some of the ones that are released into the atmosphere. This keeps the oxygen levels fairly constant in the atmosphere, and considering that the oxygen is crucial for the living organisms, this is very important. The water vapor is released into the atmosphere and it contributes to the formation of clouds, thus precipitation, clearing the air in the process. The carbon is mostly stored in them, so they manage to keep its levels stable and control the Greenhouse effect.