What is the most proable cause of super- conductivity?

Explanation

The cause of super-conductivity is that, the free electrons in super-conductor are no longer independent but become mutually dependent and coherent when critical temperature is reached. The ionic vibrations which could deflect the free electrons in metals are unable to deflect this coherent or cooperative cloud of electrons in super-conductors. That is why, there is no resistance offered by the super-conductors to the flow of electrons.