An organ is defined as separate body structures composed of multiple tissues that each perform specific functions.

• A. A single tissue
• B. Multiple tissues performing specific functions
• C. A cell
• D. A type of system

Answer: (B)

Organ structure is formed by multiple tissues working together to perform a specific function. Each tissue type—epithelial, connective, muscle, and nervous—provides a distinct part of the organ’s role, and their coordinated activity lets the organ carry out its task. For example, the heart uses muscle tissue to pump, connective tissue for support, and nervous tissue to regulate rhythm. A single tissue by itself isn’t an organ, a cell is far too small to be an organ, and a system is a group of organs working together. So an organ is defined as separate body structures composed of multiple tissues that each perform specific functions.