Answer:
In studying the origin of the universe, one of the primary unanswered questions is <u>what came before the big bang.</u>
Explanation:
The big bang theory can be described as a theory which scientists have proposed to explain how the universe came into existence. This theory predicts how the extremely hot temperatures and dense atmosphere might have given rise to the stars and the galaxies.
Scientists have no idea what happened before the big bang theory. Some scientists predict that there might be another universe which collapsed before the big bang theory. While other scientists claim that there was nothing before the big bang.
The answer is Light exposure
Because the vaccinations are producted in HK or Shanghai...
