What is the smallest functioning unit of life?

What is the smallest functioning unit of life?

• A. Tissues
• B. Cells
• C. Organs
• D. Organ systems

Answer: (B)

Life functions begin at the cell. The cell is the smallest unit that can carry out all the activities necessary for life—metabolism, growth, responding to the environment, and even reproduction. In single-celled organisms, one cell does everything, while in multicellular beings, many cells work together, but the basic working unit remains the cell. Tissues are groups of similar cells performing a common function, organs are made of tissues organized to carry out specific tasks, and organ systems are composed of multiple organs. Because those larger structures depend on cells to perform life processes, the cell stands as the smallest functioning unit of life.

Life functions begin at the cell. The cell is the smallest unit that can carry out all the activities necessary for life—metabolism, growth, responding to the environment, and even reproduction. In single-celled organisms, one cell does everything, while in multicellular beings, many cells work together, but the basic working unit remains the cell. Tissues are groups of similar cells performing a common function, organs are made of tissues organized to carry out specific tasks, and organ systems are composed of multiple organs. Because those larger structures depend on cells to perform life processes, the cell stands as the smallest functioning unit of life.