Question

this is a substance made of 2 or more elements that are chemically combined in a set ratio. this is made of 2 or more substances that are together in the same place, but their atoms are not chemically bonded. this is a substance that cannot be broken down into any other substances by physical or chemical means.

Explanation:

The first description matches the definition of a compound, which is made of two or more elements chemically combined in a fixed ratio. The second description is of a mixture, substances together without chemical bonding. The third is an element, which cannot be broken - down further by physical or chemical means.

Answer:

Compound, Mixture, Element