By the time the universe was 5 minutes old,approximately 24 percent of the normal matter in it had been turned into
A) protons.
B) neutrons.
C) hydrogen.
D) helium.

Question

Quizplus · Accepted Answer

According to current cosmological models, by the time the universe was 5 minutes old, approximately 24 percent of the normal matter in it had been turned into helium through nuclear fusion reactions. This process involved the combination of protons and neutrons. Therefore, choices A and B are not correct. While choice C is also associated with the formation of helium, it does not account for the fact that some of the normal matter would have already been converted into other elements.

By the Time the Universe Was 5 Minutes Old,approximately 24