I was about to make the recommendation to read the book snare&racket suggested.
Gravity and evolution are facts, but evolution is harder for people with low scientific literacy to understand. I was one of those people. That term is not an insult--it's just a fact for some of us who were prevented from having education in science and got brainwashed with pseudoscience instead.
That book gives a pretty good explanation of how it works. Sometimes you read rants about how stupid creationists are. Fair enough, but IMHO creation is much simpler to understand because it requires no deep thinking and no comprehension of history/physics. Evolution is a little harder to grasp if you think about it. Once you read the book, it makes complete sense.
I'm not saying creation makes actual sense. It doesn't. It's just an easy thought stopping way to explain the existence of the universe. Beginning to comprehend the universe takes a lot of logic and effort.