Can gravity be an electromagnetic force?
There are four fundamental froces in our universe:
Strong nuclear force
weak nuclear force
These forces are all different and therefore they can't be the same
Gravity is quite strongly coupled to electromagnetism.
The theory of General Relativity is quite bizarre. Electromagnetism is clearly a force propagated by the photon. Gravity is not a force.
Gravity is not a force, even though it behaves like a force. Gravity is the result of energy curving the structure of spacetime. The nearer you get to a large mass the slower time passes. This affects light in that it causes a red shift due to the time dilation causing the frequency to decrease.
So, as gravity is not a force, it can't be an electromagnetic force. It does however have strong effects due to its effects on time. Gravity causes light to bend and to change frequency.