I'm sorry nobody has told you about it yet. They should. You're scared of something just because you don't know what's in there or what it looks like. Summer school is a chance to improve your grades, because it's a class where they teach the same subjects again, so you can review it and learn it a little better than you did the first time. The only difference is that they go a little faster, because the summer is shorter than the regular school year. And that's the whole story. There's nothing to be afraid of. When I went to Summer school a few years ago, I loved it. I started to understand stuff that I didn't understand very well the first time, and I really improved my grade. Good luck.
Answer:
Life began on Earth at least 3.5 to 4 billion years ago, and it has been evolving ever since. At first, all living things on Earth were simple, single-celled organisms. Much later, the first multicellular organisms evolved, and after that, Earth's biodiversity greatly increased.
Explanation:
