Answer:
carbon dioxide hydrogen chloride carbon monoxide and nitrogen oxide
Protons are not the only subatomic particle that has a charge, electrons do to and they are negatively charged. Neutrons are situated in the nucleus of the atom, which means that they do not orbit it. Subatomic particles have different masses.
You are then left with Electrons are the subatomic particles with the smallest mass as your answer.
Looking at the following answers, and considering the definition of a biological community I believe the answer is D.
Atomic Mass is equal to the sum of the number of protons and neutrons.
Thus the atomic mass = 3 + 4
= 7
