What is considered the basic unit of all living things?

The basic unit of all living things is the cell. Cells are the fundamental building blocks of life and serve as the smallest structural and functional units of organisms. Each cell can perform all necessary life processes, including metabolism, energy conversion, and reproduction. This characteristic makes cells essential to the growth and functioning of all living organisms, from single-celled bacteria to complex multicellular organisms like humans.

Tissues, organs, and systems are higher levels of organization that are composed of multiple cells working together for specific functions, but the cell remains the fundamental unit from which these larger structures are formed. Understanding this hierarchy of biological organization is crucial in the study of anatomy and physiology, as it helps contextualize the complex interactions that occur within living organisms.