Answer:

1.A substance is simply a pure form of matter. ... Elements are the simplest form of matter, which means they cannot be broken down into smaller components physically or chemically.

2.The two main types of pure substances are compounds and elements. They consist of a single type of particle or compound.

3.A chemical substance is composed of one type of atom or molecule. A mixture is composed of different types of atoms or molecules that are not chemically bonded.

Answer:

atom or  molecule

mixture and pure substance

mixtures you cannot keep them apart sometimes they can and pure substance is pure

Explanation:

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