Which best describes a molecule?

1.a unit made of different kinds of elements.

2.a unit made of only one kind of element

3.a unit made of two or more atoms

4.a unit made of a single atom

Verified Answer :

3.a unit made of two or more atoms is the correct statement. 

Hope this helps!!

It is the first one because water is considered a molecule and it has 2 different types of atoms