A group of organs working together to perform specific and complex functions of the human body is known as a/an

O organ.
O cells.
O system.
Otissue.

system

The correct answer is "system."

The correct answer is a system. A system refers to a group of organs that work together to perform specific and complex functions in the human body. To verify this answer, you can refer to biology textbooks or reliable online sources that explain the organization of the human body. These sources typically provide information on various systems, such as the respiratory system, cardiovascular system, digestive system, and so on. Understanding the concept of systems in the human body is fundamental in biology and anatomy.