Fundamental of force in physics.

At a modern age force is divided into four categories on the basis of their property of interaction with matter to matter.

1)  GRAVITATIONAL: Gravitational force is the force of attraction that exists between two objects in the universe of mass.

G= Mm/R^2.

2)  ELECTROMAGNETIC: This force is responsible for all electrical and magnetic phenomena and is carried by photons. It is responsible for the interactions between charged particles, such as the attraction between electrons and protons in atoms and the repulsion between like charges.(it is due to spin of electron inside of the atom of specific matter)

3)   WEAK NUCLEAR FORCE: This force is responsible for certain types of radioactive decay, such as beta decay. It is a very weak force that acts over short distances and is responsible for the transformation of particles from one type to another.

4).  STRONG NUCLEAR FORCE: This force is responsible for holding the nucleus of an atom together. It is a very strong force that acts over short distances and is responsible for the stability of atomic nuclei.

At a latest research all three (electromagnetic,weak nuclear force and strong nuclear force ) are combined but gravitational force shown completely different properties to te rest of three forces. 

Some hypothesis says that gravitational force is due to graviton partical ,but it is not observed till now for researchers

these four fundamental forces are responsible for all the interactions in the universe, from the smallest subatomic particles to the largest structures in the cosmos.