What are the basic units of life?

Cells are considered the basic units of life because they are the smallest structural and functional units in all living organisms. Each cell is capable of performing essential life processes, such as metabolism, growth, reproduction, and response to stimuli. This self-sufficiency is a key feature that characterizes what it means to be alive.

While atoms and molecules build up cells, they lack the attributes of life on their own. Atoms are the smallest units of matter and combine to form molecules, which then combine to form cellular structures, but they do not exhibit the characteristics of living organisms. Tissues, on the other hand, consist of groups of similar cells that work together to perform specific functions, making them a higher level of organization than a single cell. Thus, it is the cell that is recognized as the fundamental unit from which all life is organized.