Question

quarks
which of these statements best identifies the particle that is labeled with an x?
it is either a nucleus or a proton.
it is either a proton or a neutron.
it is either a neutron or an electron.
it is either an electron or a nucleus.

Explanation:

Protons and neutrons are made up of quarks. Electrons are elementary particles not composed of quarks. Nucleus contains protons and neutrons. Since the particle X contains quarks, it can be either a proton or a neutron.

Answer:

It is either a proton or a neutron.