What is the basic unit of life?

The basic unit of life is the cell. Cells are the smallest structural and functional units in living organisms, capable of carrying out all the processes necessary for life. They can exist as independent units, as in unicellular organisms like bacteria, or as part of complex multicellular organisms, where they form tissues and organs.

Each cell contains the essential components, such as a nucleus, cytoplasm, and cell membrane, allowing it to perform vital functions like metabolism, energy conversion, and response to stimuli. Understanding that cells are the fundamental building blocks helps to establish the framework for studying biology and life sciences. The other options, while important in the hierarchy of biological organization, do not represent the most basic unit of life. An atom is a chemical unit, tissue is a group of cells working together, and an organ is a collection of tissues performing a specific function, all of which depend on cells to function.