Which term is the basic unit of life?

• A. Cell
• B. Tissue
• C. Anatomy
• D. Pathophysiology

Answer: (A)

Cells are the fundamental unit of life because they carry out all the essential processes that define living beings—metabolism, growth, responsiveness, and reproduction. The cell theory states that every living organism is composed of cells, and that new cells arise from existing cells. In multicellular organisms, cells group into tissues and organs, but life at its most basic level starts with the cell itself. Tissues are assemblies of similar cells working together, not independent life units. Anatomy is a field that studies structure, and pathophysiology examines how disease disrupts function. So the term that best identifies the basic unit capable of life is the cell.