Florida Biology EOC Practice Test 2025 – 400 Free Practice Questions to Pass the Exam

The primary role of the immune system is to defend the body against pathogens, which include viruses, bacteria, fungi, and other harmful microorganisms. This defense mechanism is crucial for maintaining health, as these pathogens can cause infections and diseases if the body does not effectively combat them. The immune system employs a variety of cells and processes that work together to recognize and eliminate these threats, such as white blood cells, antibodies, and various signaling molecules.

In contrast, the other options describe functions that are not related to the immune system. The transportation of oxygen is primarily performed by the circulatory system, specifically through red blood cells. Hormone production and regulation of body functions are functions of the endocrine system. Lastly, the absorption of nutrients occurs in the digestive system. Each system has its distinct roles, but it is the immune system that specifically targets and responds to infections and pathogens.