Here's why:

* Liquids are made up of matter: All matter is composed of atoms, which are the smallest unit of an element.

* Atoms bond to form molecules: Atoms often bond together to create larger structures called molecules.

* Liquids have a definite volume but no definite shape: In a liquid, molecules are close together but can move around freely, allowing the liquid to take the shape of its container.

Think of it like this: Imagine a crowded room full of people. They are close together but can move around, similar to molecules in a liquid.