Answer:
A scientific theory is a well-substantiated explanation of any natural phenomenon. The theory is proposed on the basis of the performed experiments and careful examination of the facts derived from the previous experiments.
The theory is an elaborate form of a hypothesis as a hypothesis is the limited explanation of any natural phenomenon but the theory is a detailed and deep explanation of the phenomenon.
The theory of relativity was proposed by the Albert Einstein in 1905 which was supported by the repeated experiments by the researcher and scientists in 1919 when a solar eclipse was observed.