Fundamental interactions, also known as fundamental forces, are the basic ways in which particles interact with each other in the universe. There are four known fundamental interactions: gravitational, electromagnetic, strong nuclear, and weak nuclear forces. Each of these forces plays a crucial role in governing the behavior of matter and energy, from the smallest particles to the largest structures in the cosmos. The gravitational force attracts objects with mass, while the electromagnetic force affects charged particles, enabling electricity and magnetism. The strong nuclear force binds protons and neutrons in atomic nuclei, and the weak nuclear force is responsible for certain types of radioactive decay. Together, these interactions form the foundation of all physical phenomena.