What is the basic unit of life?

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

Answer: (B)

Cells are the basic units that carry out life processes. They perform metabolism, grow, respond to the environment, and can reproduce. In all living things, these activities happen at the cellular level. In multicellular organisms, cells group together to form tissues, tissues make up organs, and organs build up the whole organism, but the cell remains the smallest unit capable of life. An organism is the whole living thing, often composed of many cells; a tissue is a group of similar cells working together; an organ is a structure made of different tissues with a specific function. So the cell best fits as the fundamental unit of life.