Are you referring to the fact that water is a compound while hydrogen is an element? If I'm wrong just comment and clarify and I can edit it, I don't even know what kind of unit you're in. :)
Answer:
Four fundamental forces are gravitational, electromagnetic, strong, and weak.
Explanation:
The gravitational and electromagnetic interactions, which produce significant long-range forces whose effects can be seen directly in everyday life and the strong and weak interactions, which produce forces at minuscule, subatomic distances and govern nuclear interactions.
From what I can see it's D, I did this by simply examining the other answers and seeing that they are beneficial, so, from that information, this one must not be.
<u>Answer:</u>
For a. Neutrons and electrons also form an atom.
For b. The element is oxygen which is a non-metal and will form a negative ion while forming ionic bond.
<u>Explanation:</u>
There are 3 subatomic particles which form an atom. These are neutrons, protons and electrons.
Neutrons carry no charge, protons carry positive charge and electrons carry negative charge. Neutrons and protons are present in nucleus and electrons revolve around the nucleus.
The energy which is present between neutrons and protons are nuclear energy and the energy which is present between electrons and protons are electrostatic energy.
In an element, number of protons is always equal to the number of electrons. The atomic number is equal to the number of protons or electrons. The element which has atomic number 8 is Oxygen.
The electronic configuration of this element is 
This element requires only 2 electrons to form a stable electronic configuration. An element which gains electron is considered as a non-metal and forms a negative ion because number of electrons increases.