The fourth category is the strong nuclear force, which holds the quarks together in the proton and neutron, and holds the protons and neutrons together in the nucleus of an atom. It is believed that this force is carried by another spin-1 particle, called the gluon, which interacts only with itself and with the quarks.
| Game | Time | WPM | Accuracy |
|---|---|---|---|
| 28 | 2019-02-03 01:03:53 | 68.88 | 98% |