Final answer:
The basic unit of life is the cell, which is the foundational component of all organisms and crucial to the functions of human physiology.
Step-by-step explanation:
The cell is the basic unit of life. It is the smallest independently functioning biological unit of an organism. All living organisms are composed of one or more cells, and the functions of human physiology are performed in cells or initiated by cells. This makes cells the basic building blocks of all organisms, whether they are single-celled like bacteria or multicellular like humans. The unified cell theory elaborates on this by stating that all organisms are composed of cells, the cell is the basic unit of life, and new cells arise from pre-existing cells.