Ascientist uses an accelerator and high energy electrons to study the particles inside the protons of a helium atom. what particles is the scientist studying?
a. the he neutrons
b. the he nucleus
c. the he electrons
d. the he quarks

Together, neutrons, protons and electrons form an atom. If he wants to study particles inside protons that means he cant study:
Neutrons and electrons.

Nucleus is core of an atom. It is made out of protons and neutrons. So that is not answer as well.

The answer is D, quarks. Quarks are very small particles that are making protons...