Okay kiddo, let's talk about something called "rebuttable presumption." This is a fancy way of talking about a situation where people believe one thing is true, but someone else can come along and prove that it's not true.
Here's an example: let's say that people generally believe that all dogs are nice and friendly. This means that there is a "presumption" that all dogs are nice and friendly. But what if someone meets a dog who is mean and tries to bite them? They can "rebut" the presumption by showing that not all dogs are nice and friendly.
In the legal world, rebuttable presumption happens a lot. For example, if someone is accused of a crime, the prosecutor might argue that the person is guilty unless the defendant can prove otherwise. This is a rebuttable presumption of guilt.
So, in summary, rebuttable presumption means that people believe something is true, but it can be proven otherwise. It's kind of like when you think you know something for sure, but someone shows you that you were wrong.