Which option correctly identifies the term for a living thing?

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

Answer: (D)

Organism is the term for a living thing. An organism is any individual life form capable of carrying out life processes such as metabolism, growth, reproduction, and responding to the environment. This includes single-celled entities like bacteria as well as multicellular beings like plants and animals. The other terms describe parts or groups within an organism: tissue is a group of similar cells performing a function, an organ is a structure made of tissues that carries out a specific task, and a system is a set of organs working together to perform broader functions. Because “organism” names the whole living being, it’s the best choice for identifying a living thing.