Answer:
"The theory of relativity"
Step-by-step explanation:
The theory of relativity includes both the theory of special relativity and general relativity, formulated by Albert Einstein in the early twentieth century, which sought to resolve the incompatibility between Newtonian mechanics and electromagnetism.
The theory of special relativity, published in 1905, deals with the physics of the movement of bodies in the absence of gravitational forces, in which Maxwell's equations of electromagnetism were made compatible with a reformulation of the laws of motion.
The theory of general relativity, published in 1915, is a theory of gravity that replaces Newtonian gravity, although it coincides numerically with gravity for weak gravitational fields and "small" velocities. The general theory is reduced to the special theory in the absence of gravitational fields.