Ok kiddo, do you know when you touch something hot and your hand jerks away really fast without you thinking about it? That's your body reactively protecting itself from harm.
Body reactivity is when your body automatically responds to certain situations without you needing to think about it first. For example, when you get scared, your body might start to sweat and your heart might start to race.
These reactions happen because your brain has a special system that helps you respond to different situations quickly and effectively. It's like having a superpower that helps you stay safe and healthy!
Sometimes, though, your body can react too much or in unusual ways. Like if you have an allergy to peanuts, your body might react really strongly to even a tiny bit of peanut. In that case, it's important to be careful around peanuts and to let other people know about your allergy so they can help keep you safe.
So, that's body reactivity in a nutshell - it's like a superpower that helps keep us safe, but sometimes we need to be careful to make sure it doesn't go into overdrive.