What is the basic unit of life?

What is the basic unit of life?

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

Answer: (A)

Life starts at the cell, so the basic unit of life is the cell. It’s the smallest structure that can carry out all the functions that define living things—using energy, growing, reacting to the environment, and reproducing. Cells have the necessary components, like a membrane to separate inside from outside and genetic material to guide activity, that allow them to perform these life processes. Some organisms are single-celled and do everything within one cell, while others are multicellular and built from many cells working together. Molecules are just chemical building blocks and aren’t alive by themselves, so they can’t carry out life processes. Tissues and organs are larger assemblies made from cells, not the smallest unit that can live.

Life starts at the cell, so the basic unit of life is the cell. It’s the smallest structure that can carry out all the functions that define living things—using energy, growing, reacting to the environment, and reproducing. Cells have the necessary components, like a membrane to separate inside from outside and genetic material to guide activity, that allow them to perform these life processes. Some organisms are single-celled and do everything within one cell, while others are multicellular and built from many cells working together. Molecules are just chemical building blocks and aren’t alive by themselves, so they can’t carry out life processes. Tissues and organs are larger assemblies made from cells, not the smallest unit that can live.