water and ammonia are polar. The hydrogen atoms in each have a slight positive charge. What does that tell you about the oxygen atom in water and the nitrogen atom in ammonia?

More electronegative

Explanation:

The oxygen and nitrogen in ammonia shows that they are more electronegative than the hydrogen  atoms.

Electronegativity shows the affinity of an atom for valence electrons. Electronegativity is the measure of the relative tendency with which the atoms of the element attract valence electrons in a chemical bond.

The oxygen atom in water and the nitrogen atom in ammonia are more electronegative.

They attract the electrons more and they then become negatively charged.

The hydrogen will then become positively charged in the shared covalency.

The correct pairing of the volcano to its formation would be the composite volcano wherein it usually yields large and violent eruptions. In addition to that, composite volcanoes or also known as the stratovolcano is usually made of materials containing increasing layers of hardened lava.