Which statement is true about organ systems?

• A. It is a group of organs working together to perform a function
• B. It is a single organ
• C. It is a tissue
• D. It is a cell

Answer: (A)

Organ systems are made up of multiple organs that work together to perform a complex function necessary for the organism’s life. Each organ handles a part of the task, but only their collaboration achieves the full function—for example, in the circulatory system, the heart pumps blood, blood vessels carry it through the body, and blood vessels and blood work together to deliver oxygen and nutrients and remove wastes.

A single organ is just one structure, like the heart or the liver, not a coordinated set of parts. A tissue is a group of similar cells performing a shared job, such as muscle tissue or nervous tissue. A cell is the basic unit of life, the smallest unit that can carry out life processes on its own.