What is the smallest unit of life?

The smallest unit of life is the cell. Cells are the basic building blocks of all living organisms, and they are capable of performing all the essential functions necessary for life, such as metabolism, growth, reproduction, and response to the environment. Each cell can operate independently and carry out vital processes for the organism as a whole, whether it functions alone, like in single-celled organisms, or as part of a larger system in multicellular organisms.

Atoms and molecules, while important components of cells, do not represent life themselves; they are the chemical foundations that make up cells. Tissues are groups of cells that work together to perform specific functions but cannot be considered the smallest unit of life since they are already comprised of cells. Therefore, the cell is recognized as the fundamental unit that embodies the characteristics of living organisms.