How do bacteria improve the soil? How people use bacteria.

Bacteria recycle dead organic matter, thereby increasing soil fertility. Bacteria are used by humans to obtain medicines, hydrogen bacteria are used to create an atmosphere in artificial life support systems (spaceships). Bacteria are participants in the biological cycle of substances, as well as the cycle of chemical elements of sulfur, iron and many others. Some bacteria, for example, nitrogen-fixing bacteria, are involved in the nitrogen cycle and enter into symbiosis with the roots of leguminous plants.