but here in the US there aren't much butterflies anywhere except maybe parks.

As someone that lived in the USA for over 20 years I can say that you are correct. I don't know why that is. Have you seen a monarch butterfly yet? Those were the only common ones I remember from when I was your age. They are lovely, but they are poisonous and this is why there are so many of them. The other insects know that if they eat this one, they will die... or something like that. Don't tell your science teacher some random guy on the internet knows more than she does because I don't.

Also, I am amazed at how well you speak English now. You must be really smart!