Each cell attains and processes to maintain homeostasis which is defined as the balance between the internal and external environment, adapting for instance for a cell to survive. That is why, the follow of water and other gradients is gradual and continuous.
A person will develop fever that will increase a person's normal body temperature from 37C to about 38-41C, depending on the conditions. This bodily reaction is caused by many microorganisms that may have invaded the host's body or the individual's visceral parts with that said, many bacteria cannot multiply under hot temperatures and spread throughout the body system. This is one way of the human body to restore its physiology into a normal state -homeostasis, unless these microorganisms are fully eradicated and the body is neutralized there is no balance or homeostatic state.