Both answer the question, "Why?"
Why does something happen?
Why does a tree need water?
Why do people need to sleep?
Why do people get fevers when they are sick?
Why do I think LeBron James is such a great basketball player?
Why do I think my mother (or father, or teacher) is the most amazing person I know?
When you write your three reasons, remember to save the most important for last
Why just three reasons? Because when you add more, it becomes a list. When you have only two it's probably not going to be enough to write an essay.
Once you have the basic form, developing the full paragraph and short essay is a matter of adding details and examples.
