Protons and neutrons are composed
a. molecules
b. ions
c. quarks
d. electrons

Protons and neutrons are composed of quarks

C ( quarks)

Protons and neutrons consists of quarks.

Option C

Explanation:

The “elementary particle and fundamental constituent of matter” is known as quark. Quarks mix up to form “composite particles called hadrons”. The stable are protons and neutrons, which are the “components of atomic nuclei”.

Atoms consists of two particles electrons and quarks. Quarks are composed of protons and neutrons. There are three quarks in each proton and neutron. Many varieties of quarks available.  

Up quark and down quark are its types. There are “two up quark and one down quark” in the proton. There are “one up quark and two down quark” are there in the neutron.

the part of the wave he is travelling on is the crest

c) up is the direction the magnetic force is acting on the charge.