The correct answer is E) The human body is subject to a chemical process.
Hailey is writing about the anatomy of the human body. She identifies that most of the human body is water. The conclusion she can draw from this fact is "The human body is subject to a chemical process."
The chemical process of the human body is amazing. In this case, water is so much needed in the blood of a human body to help transport all the nutrients to the different parts of the body. The cells need those nutrients to function correctly and keep the body hydrated and maintain good health. So it is appropriate that you constantly drink water to maintain the hydration of your entire body.