The humors theory states that a balance of how many body fluids is essential for health?

The humors theory, which dates back to ancient Greek medicine, posits that health is maintained by a balance of four bodily fluids, also known as humors. These four humors are blood, phlegm, black bile, and yellow bile. Each humor is associated with different temperaments and aspects of health. The theory suggests that an imbalance among these humors could lead to illness, which was a common framework for understanding health and disease in various historical contexts. Therefore, since the theory explicitly identifies four distinct fluids that need to be balanced for optimal health, the answer is correct. Understanding this concept is vital in recognizing how historical medical practices and beliefs have shaped contemporary views on health and illness.