There is no known beginning so they cant see how it started to form or how to cure it, the virus is also very difficult to predict what it is going to do, it is similar to cancer it could sit around and do nothing or one day it could go wild and kill somone
Answer:They are similar because they both help you. They are different by How they use oxygen,How long it takes,The rate of your heartbeat,How your energy is spent,and How they benefit you.
