Final answer:
Pyrexia, febrile, and pyrogenic all refer to fever, which is a system-wide sign of inflammation that raises the body temperature and stimulates the immune response.
Step-by-step explanation:
The terms pyrexia, febrile, and pyrogenic all refer to fever. Fever is a system-wide sign of inflammation that raises the body temperature and stimulates the immune response. It is a result of the immune system's response to certain pathogens, where pyrogens are released that cause the body temperature to rise. Fever helps create an unfavorable environment for pathogens and aids in cellular repair processes.