Which term describes a living thing?

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

Answer: (B)

Understanding what describes a living thing: an organism. An organism is any living being that can carry out the basic life processes, such as metabolism, growth, and reproduction. It can exist as a single cell in unicellular organisms or as many cells in multicellular ones, but the term refers to the whole living entity rather than just a part. The other options describe parts or levels within an organism: a cell is the smallest unit of life; tissue is a group of similar cells performing a function; organ systems are groups of organs that work together. All of these are parts that can make up an organism, but the word that names the entire living thing is organism.