Bill Hoover, age 9, of Phoenix, Ariz., for his question:

WHAT MAKES A PERSON'S TEMPERATURE RISE?

A person's body temperature is generally 98.6 degrees Fahrenheit. Because your body is always producing heat through the burning of food that has been eaten, i,t is necessary that heat be lost. Your body temperature would rise about four degrees every hour if there weren't a way for the heat to escape. Body heat escapes mainly through the skin's surface and also by evaporation from the lungs.

Much heat is produced when a muscle contracts, and that's why exercise makes us feel warm. Heat is also constantly being produced by our livers. Blood circulation takes the heat from the hottest places in the body, such as the liver, and carries it to the coolest places, such as our fingers and toes.