The ideas that the universe began at a single point and has been expanding since its formation are the main premises of which of the following? a. the big bang theory b. nucleosynthesis c. redshifting d. the big crunch theory

The big bang theory describes and claims that the universe has been created through cosmic expansion originating from a single point.

Where it was explained that the nature of now objects in space being in constant space was due to once a high density and high density point produce a scattering or explosion of the cosmic energy . Other theories have also supported this theory originally and first documented by Georges Henri Joseph Édouard Lemaître an astronomer and physicist.

That depends on what kind of environ meant it is in  in space it has the same force that was applied when the velocity was gained