Which term describes the smallest unit of life?

• A. Atom
• B. Molecule
• C. Cell
• D. Organ

Answer: (C)

Consider what makes something alive: life functions are carried out by cells. A cell is the smallest unit capable of performing the activities that define living things, such as metabolism, growth, responding to the environment, and reproduction. This idea is captured by cell theory: all living things are composed of cells, and cells arise from pre-existing cells. While atoms and molecules are essential building blocks of matter, they do not carry out life processes on their own. An organ, on the other hand, is a structure made of tissues that performs a specific function, not the basic unit of life. So, the smallest unit of life is the cell.