What is one major role of the immune system?

The immune system’s primary role is to defend the body from foreign invaders, such as bacteria, viruses, parasites, and other pathogens that can cause disease. It accomplishes this complex task through various components, including white blood cells, antibodies, and other substances that identify and neutralize harmful entities. This defense mechanism is vital for maintaining health and preventing infections. When the immune system encounters a pathogen, it triggers an immune response, which can involve the activation of various types of immune cells that recognize and respond specifically to threats, ultimately protecting the body from illness.

In contrast, regulating body temperature is primarily the role of the hypothalamus within the central nervous system, while hormone production is mainly associated with the endocrine system, which includes glands like the thyroid and pancreas. Digestion, on the other hand, is the responsibility of the digestive system, which processes food and absorbs nutrients. Each of these systems has distinct functions that contribute to overall health, but the immune system's unique focus on defense against pathogens is what sets it apart.