Which statement is part of the Big Bang theory

Question

The chemical makeup of the universe has changed dramatically
Small spiral galaxies become larger elliptical galaxies
The universe began as a very high density singularity
Dark Matter makes up the majority of matter in the galaxy

Answer 1

The statement that is part of the Big Bang theory is:

The universe began as a very high density singularity.

The Big Bang theory posits that the universe originated from an extremely hot and dense state and has been expanding ever since. The other statements relate to different aspects of cosmology and galaxy formation, but they are not direct components of the Big Bang theory itself.