Extreme heat is defined as summertime temperatures that are much hotter and/or humid than average. Heat-related illnesses, ＿＿（41）＿＿ heat exhaustion or heat stroke, happen when the body is not able to properly cool itself. In such cases, a person's body temperature rises faster ＿＿（42）＿＿ it can cool itself down. This can cause damage to the brain and ＿＿（43）＿＿ vital organs. The following are tips for preventing heat-related illnesses: * Stay Cool Indoors: Stay in an air-conditioned place as much as possible. * ＿＿（44）＿＿ Outdoor Activities Carefully: Try to limit your outdoor activity to ＿＿（45）＿＿ it is coolest, like morning and evening hours. * Know the Signs: Learn the signs and symptoms of heat-related illnesses and how to treat them.