Praxis II Science (7814) Practice Exam

The main function of the immune system is to defend against pathogens, which includes viruses, bacteria, fungi, and parasites that can cause disease. This system is composed of various cells, tissues, and organs that work together to identify and eliminate these harmful invaders. The immune response can be either innate, providing immediate but general protection, or adaptive, which develops a targeted response based on specific pathogens and involves the production of antibodies for future defense. The other options focus on different biological functions that are not related to the immune system. For instance, regulating metabolism pertains to the processes that convert food into energy, transport hormones involves the circulatory system distributing hormonal signals throughout the body, and digesting nutrients is a function of the digestive system that breaks down food into absorbable components. Understanding the immune system's critical role in maintaining health helps highlight its importance in protecting the body from disease.