This was probably the predominant gas in Earth's earliest atmosphere:
A)argon.
B)hydrogen.
C)water vapor.
D)nitrogen.

Question

Quizplus · Accepted Answer

The earliest atmosphere of Earth is thought to have been primarily composed of hydrogen, with traces of other gases such as helium and methane. This atmosphere was likely formed through volcanic outgassing and was later transformed into the current atmosphere through processes such as the evolution of photosynthetic organisms.

This Was Probably the Predominant Gas in Earth's Earliest Atmosphere