The four primary forces of nature are gravity, electromagnetism, the strong nuclear force, and the weak nuclear force. Gravity is the force that attracts objects with mass towards each other, while electromagnetism governs interactions between charged particles. The strong nuclear force is responsible for holding protons and neutrons together in an atomic nucleus, whereas the weak nuclear force plays a critical role in nuclear decay and reactions. Together, these forces explain the vast array of interactions that occur in the universe.