Which level of organization includes multiple tissues that work together to perform closely related functions?

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

Answer: (C)

The level described is an organ. An organ is made up of several types of tissues that work together to perform a specific, coordinated function. For example, the heart contains muscle tissue to contract, connective tissue to support and anchor structures, and nervous tissue to help regulate rhythm. Similarly, the stomach combines epithelial tissue to line its interior, smooth muscle tissue to churn contents, and connective tissue to provide support, all collaborating to digest and move food. A tissue is just a group of similar cells doing a common job, and a cell is the basic unit of life. An organ system is a broader level where multiple organs cooperate for larger bodily functions, like the digestive system as a whole.