Tairaa: If you look at all the forces, they form a tree. Electricity and Magnetism are leaves on that tree. Their parent node is Electro-Magnetism. The Weak force leaf and Electro-Magnetism's parent node is the Electro-Weak force. Add the Strong force to Electro-Weak and get the Unified force. This combining is possible with greater understanding the forces and happens with higher temperatures. At the beginning of the universe the temperature was so high that all the forces were one. But our current theories have not brought in line the Gravitational forces (there are 2, Terrestrial Gravity and Interstellar Gravity). We should be able to bring those 2 together and then bring that together with the UF to form the Grand Unified force. So far no go but there are some interesting theories; their are Quantum theories of Gravity.
All of the forces were "solidified" out as the universe cooled and the forces separated. So it follows that our understanding of gravity is flawed. I believe Relativity is ultimately wrong. Sorry Albert.