The biosphere is the part of the earth that supports life forms. It includes hydrosphere, atmosphere, and lithosphere. Various ecosystems, aquatic or terrestrial, are present in the biosphere. Biotic and abiotic components of a geographical region that interact with each other together make an ecosystem.
The biotic component of an ecosystem includes all the organisms present in it. Organisms may be unicellular or multicellular. All the organisms are made up of one or more cells. Cells are made up of various biomolecules that interact and enable cells to perform the life processes.