Answer:
Pyrogens are substances which, when injected into the mammalian body, will cause a variety of symptoms, the most recognisable of which is an increase in core body temperature.
Step-by-step explanation:
The body is able to regulate temperature in response to signals from the nervous system. When bacteria are destroyed by leuckocytes, pyrogens are released into the blood. Pyrogens reset the body's thermostat to a higher temperature, resulting in fever.