By definition, we have to:
A molecule is a group of at least two atoms in a defined configuration linked by chemical bonds.
We have two types of molecules:
1) several atoms of a single chemical element, as in the case of oxygen. (O2)
2) Atoms of different elements, as in the case of water. (H2O)
Answer:
the best description of a molecule is:
A: A molecule of an element is composed of at least two types of atoms.
