Which condition or component was not likely to have been present on Earth during the formation of the first biologically relevant molecules?

Question

Quizplus · Accepted Answer

High atmospheric oxygen levels were not likely to have been present during the formation of the first biologically relevant molecules, as oxygen was likely introduced to Earth by photosynthetic organisms after the origin of life. The other conditions/components (rain, electrical activity, ammonia gas, and hydrogen gas) could have been present and potentially contributed to the formation of biologically relevant molecules.

Which Condition or Component Was Not Likely to Have Been