What is the basic structural and functional unit of life?

The cell is recognized as the basic structural and functional unit of life due to its ability to perform all necessary life processes. Cells are the smallest units that can carry out activities such as metabolism, growth, reproduction, and response to stimuli. This characteristic distinguishes cells from larger biological structures like tissues and organs, which are composed of groups of cells working together to perform specific functions.

Each type of cell has its own unique functions and roles, contributing to the overall functioning of an organism. For instance, muscle cells are specialized for contraction, while nerve cells are adapted for signal transmission. In multicellular organisms, cells collaborate to form tissues—groups of similar cells—and these tissues come together to create organs, which have specialized functions.

Moreover, every organism, from single-celled bacteria to complex multicellular beings like humans, begins life as a single cell, emphasizing the cell's fundamental role in life.