The smallest unit of life is the cell. Cells are the fundamental structural and functional units of all living organisms, capable of independent existence and performing all necessary life processes such as growth, reproduction, and metabolism
. Cells can be unicellular, as in bacteria and many microorganisms, or multicellular, as in plants and animals. They consist of various components including a cell membrane, cytoplasm, and, in eukaryotes, a nucleus that contains genetic material
. Unlike atoms, molecules, organelles, or macromolecules, cells are the smallest entities that meet all criteria for life independently
. In summary, the cell is the smallest unit that can independently carry out life functions and reproduce, making it the basic building block of all living things.
