In biology, what is the basic unit of life?

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

Answer: (B)

Cells are the smallest units that can carry out all life processes. They perform metabolism, use and transform energy, grow, respond to their environment, and reproduce. In multicellular organisms, many cells specialize and organize into tissues, tissues form organs, and organs make up organ systems, but life begins at the cell. Molecules are just chemical building blocks and can’t carry out life processes on their own. Tissues are groups of similar cells working together, and organs are larger structures made of tissues performing particular tasks. So, the cell is the basic unit of life because it can independently carry out the functions that define living things and serves as the foundation for all other levels of biological organization.