Why do humans dream, and what are the leading theories about it?

Humans dream because their brains are busy working hard while they sleep, and dreams help them organize what happened during the day, like when you sort your toys after playing.

Imagine your brain is like a robot that takes notes all day. When you go to bed, it starts cleaning up those notes. Sometimes, it makes fun little stories out of them, that's your dream!

Some scientists believe dreams help you remember important things, like where you left your favorite toy.

Others think dreams are like a brain exercise, they help your brain get ready for the next day, just like how you practice jumping to get better at it.

And some say that when you dream, your brain is trying to solve problems or work out tricky situations from the day, like figuring out how to share your snacks with friends.