Why do individuals with low levels of fitness die?

How do adaptations help an organism as they struggle for existence?

Not getting enough physical activity can lead to heart disease—even for people who have no other risk factors. It can also increase the likelihood of developing other heart disease risk factors, including obesity, high blood pressure, high blood cholesterol, and type 2 diabetes.

Darwin suggests that an organism's struggle for existence is part of what determines why some species' characteristics survive and others become extinct. These adaptations illustrate how unique characteristics of particular organisms have developed, allowing them to thrive in their specific environments.

the match lol

sorry to break it to ya but no one can answer your question it's just

jk but i am serious about the part that most people cant answer it beacuse you did not mention the section you are talking about. but it would if you added some detail and were a bit more specific.