How might pyrogens cause the body temperature to rise

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.

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.

his research revealed two genetically different groups of prokaryotes, which justified splitting kingdom monera into two kingdoms. the genetic and cellular differences were so great, that these two kingdoms were eventually placed into different domains in the current three-domain system.