Question

which of the following observations would indicate that a material is a pure substance? it does not dissolve in water. it changes color after heating. it cannot be physically broken down into different types of atoms. it can be physically broken down into different types of molecules.

Explanation:

A pure substance is made up of only one type of atom or molecule and cannot be physically broken down into different types of atoms. Not dissolving in water or changing color after heating don't define purity. Being able to be broken into different molecules means it's a mixture.

Answer:

It cannot be physically broken down into different types of atoms.