Which term refers to the basic units of structure and function in living things?

• A. Organelles
• B. Cells
• C. Tissues
• D. Organs

Answer: (B)

Cells are the basic unit of structure and function in living things. This idea comes from cell theory, which states that all living things are made of cells, and that cells are the smallest units capable of carrying out life’s essential processes. Even single-celled organisms rely on a single cell to perform metabolism, growth, and reproduction, while multicellular organisms are composed of many cells that specialize to perform different tasks. Inside a cell, organelles carry out specific functions, but they only work within the cell itself and do not operate as independent life units. Other terms describe higher levels of organization: organelles are parts within a cell, tissues are groups of similar cells, and organs are structures made of tissues that perform particular functions. Because cells are the fundamental units that do everything necessary for life, they are the correct term.