Which of these is true about pure substances? A. They may contain one type of atom or one type of molecule.
B. They can contain different types of atoms and molecules.
C. They can only contain one type of molecule.
D. They can only contain one type of atom.

B. They can contain different types of atoms and molecules.

Explanation:

A pure substance only has one type of particle that can either be atoms, molecules, elements, or compounds.

a) the particles of the chair are strongly held together.

diaria maybe go see a doctor about that