Question

a water molecule is made of
two atoms of hydrogen and one atom of oxygen.
an oxygen atom.
a hydrogen atom.
rewatch

Explanation:

The chemical formula of water is $\text{H}_2\text{O}$, which denotes the composition of a single water molecule. This formula confirms it contains 2 hydrogen atoms and 1 oxygen atom, while the other options only name one type of atom, which is incomplete.

Answer:

two atoms of hydrogen and one atom of oxygen.