After the Big Bang, as the universe cooled and protons and electrons combined, what important consequence happened?
A) Protons and neutrons combined to form nuclei such as deuterium and helium.
B) Neutrinos ceased to interact with normal matter.
C) Dark matter ceased to interact with normal matter.
D) Photons began to travel freely through the universe.
E) Lithium and other light elements were formed by the fusion of hydrogen and helium.

Question

Quizplus · Accepted Answer

As the universe cooled, protons and electrons combined to form neutral hydrogen atoms, allowing photons to travel freely, leading to the Cosmic Microwave Background radiation.

After the Big Bang, as the Universe Cooled and Protons