What is the basic unit of life?

The basic unit of life is a cell. Cells are the smallest structural and functional units in all living organisms. They can carry out all the processes necessary for life, including metabolism, growth, and reproduction. In multicellular organisms, cells can specialize to perform distinct functions, but they all originate from pre-existing cells through the process of cell division.

Atoms and molecules, while fundamental components of matter, do not meet the criteria for life on their own. An atom is the smallest unit of an element, and molecules are composed of two or more atoms bonded together, but neither represents the processes that define living organisms. Tissue, on the other hand, is a group of similar cells that work together to perform a specific function, but it is not the basic unit of life itself. Thus, the cell is correctly identified as the fundamental building block of all living things.