Between heaven and earth, the state of living things is different, and they take carbon sources, which are autotrophic and heterotrophic.

Autotrophs can be nourished by inorganic carbon sources. Such as plants, with the wonders of photosynthesis, they absorb carbon dioxide into the body, and with the energy of light and heat, turn water and gas into sugars and other things, in order to establish a foundation for life. It relies solely on the power of nature, and supports its own growth and reproduction. It does not need other things to supply carbon, but can stand on its own in the world, which seems to have outstanding ability.

Heterotrophs, not so. They cannot live from inorganic carbon sources, but must rely on external organic carbon sources. If they move, or eat plants, or eat other things to obtain organic carbon. The food is digested and metabolized, and the carbon source enters the body for its energy needs and body construction. Its life also depends on other things, and each has its place in the chain of ecology.

Autotrophic and heterotrophic, as far as carbon sources are concerned, although the path is different, they are both methods of survival. The prosperity of ecology depends on the coexistence of the two, and they cooperate to achieve. Autotrophs are solid, heterotrophic follow the chain, symbiosis and co-prosperity, so as to maintain the endless vitality of heaven and earth.