Fundamental forces, also known as fundamental interactions, are the fundamental interactions that govern the behavior of particles in the universe. These forces are responsible for all physical phenomena we observe, from the motion of planets in the solar system to the behavior of subatomic particles. There are four known fundamental forces:

1. Gravitational Force: The gravitational force is the force of attraction that exists between all objects with mass. It is described by Isaac Newton's law of universal gravitation and is responsible for the attraction of objects towards each other. In the realm of astrophysics, it governs the motion of planets, stars, and galaxies.

2. Electromagnetic Force: The electromagnetic force is responsible for the interactions between charged particles. It includes both electric and magnetic forces. It is described by Maxwell's equations and is responsible for a wide range of phenomena, including the behavior of charged particles, the properties of light, and the operation of electrical circuits.

3. Weak Nuclear Force: The weak nuclear force, or weak interaction, is responsible for processes such as beta decay in atomic nuclei and is responsible for changing one type of subatomic particle into another. It is associated with the exchange of W and Z bosons.

4. Strong Nuclear Force: The strong nuclear force, or strong interaction, is the force that holds protons and neutrons together in the nucleus of an atom. It is mediated by particles called gluons and is one of the strongest forces in nature. This force is responsible for the stability of atomic nuclei.