What are organs?

• A. Different types of tissues organized into functional units
• B. Groups of cells performing similar tasks
• C. Body parts that perform only one function
• D. A collection of organs

Answer: (A)

An organ is a structure in the body formed when different tissue types come together to perform a coordinated task. Tissues such as muscle, connective, epithelial, and sometimes nervous tissue join to create a functional unit that can carry out a specific job—like the heart pumping blood or the liver processing chemicals. This integrated build is what distinguishes an organ from a tissue, which is just groups of similar cells. Many organs actually have multiple roles, so saying they perform only one function isn’t quite accurate. A collection of organs, on the other hand, makes up an organ system, not a single organ.