Final answer:
Heat illness can have serious and potentially fatal symptoms including fever, fatigue, dehydration, and organ failure. Seeking medical help and taking precautions in hot environments is crucial.
Step-by-step explanation:
Heat illness may present life-threatening symptoms including fever, fatigue, dizziness, headache, nausea, vomiting, and dehydration. In more severe cases, symptoms can progress to include organ failure, seizures, shock, and even death. It is important to seek immediate medical attention and take preventive measures in hot environments to avoid heat illness.