Which system in the body functions to fight disease?

The immune system is the body's primary defense mechanism against pathogens, such as viruses, bacteria, and other foreign invaders. It includes a complex network of cells, tissues, and organs that work together to identify and neutralize harmful substances. Key components of the immune system include white blood cells, antibodies, lymph nodes, and the spleen, among others.

When the body detects an infection or disease, the immune system mobilizes its resources to target and eliminate the pathogens. This system not only defends against current infections but also establishes a memory that helps the body recognize and respond more effectively to future attacks by the same pathogens.

In contrast, the circulatory system primarily functions to transport nutrients, oxygen, hormones, and waste products throughout the body. The nervous system is responsible for transmitting signals between different parts of the body and coordinating bodily functions. The endocrine system regulates various bodily processes through hormones but does not directly fight disease. Thus, the immune system stands out as the dedicated protector against disease within the body.