Heh. When my boy was around 6 or 7, he asked why squirrels have bushy tails. I told him I wasn’t certain, but I thought it was because healthy squirrels with lots of food have bushier tails, so the girl squirrels would pick them to be the daddies, so their babies would probably be well fed, too. Over time, squirrels with bushy tails would start to outnumber scraggly tails.
(Not sure if that’s the real “reason” or not, but it was an attempt to start a very early understanding of evolution - that some traits attract mates, and become more frequent in the population.)
He kept walking, slowly, head down, shoulders up. I could tell that answer didn’t satisfy him one bit. So, mostly joking, I said, “Or some people think God was making all the animals and thought, ‘What would happen if I gave this one here a gigantic poofy tail?’ and that was the beginning of squirrels.”
Shoulders went down, head came up, step quickened and he grinned. “Yeah, I like that one.”
So, for some reason, the kid needed to hear that day that squirrels have bushy tails because God made them that way. Same kid who’s agnostic now, nearly 21. He understands, and accepts evolution now, and isn’t much interested in “God did it,” explanations.
Parenting is not a one day process. You don’t have to teach them everything today. They’ll get to it when they’re ready for it, if you just follow their lead and stay in tune with their needs.