Inside protons and neutrons, there are fundamental particles called quarks.

Protons and neutrons are made up of even smaller particles called quarks.

These particles are made of even smaller subparticles called quarks and gluons.

The notion was that virtually all such particles were composed of a few simpler particles called quarks.

According to quantum theory, each is made of three particles called quarks.

These neutrons and protons are made up of smaller particles called quarks.

They respond to electric fields because they contain charged particles called quarks.

They are made up of elementary particles called quarks.

For the sake of efficiency, integers called quarks are defined to represent local strings.

Latest experiments show that a proton is made of three smaller particles called quarks.