Which term is defined as a living thing?

• A. A living thing
• B. Organism
• C. Structure
• D. System

Answer: (B)

The main idea is how biologists name living beings. An organism is the living thing itself—a single cell or many cells that can carry out life processes like metabolism, growth, reproduction, and response to the environment. This term specifically defines a living entity, from bacteria to plants to animals.

A structure is any part of a body, not the living status of the whole being. A system refers to a group of organs or parts working together, not to the living thing as a whole. Saying “a living thing” is just a descriptive phrase, not the formal term used to classify life. So the best term for a living thing is organism.