The early atmosphere of Earth probably did not contain ____.

Question

Quizplus · Accepted Answer

The early atmosphere of Earth is believed to have been composed mainly of nitrogen, carbon dioxide, water vapor, and small amounts of other gases such as methane, ammonia, and sulfur dioxide. Oxygen was not present in significant amounts at that time as it was only introduced into the atmosphere later through the process of photosynthesis by early photosynthetic organisms. Carbon monoxide may have been present, but its abundance is not well known.

The Early Atmosphere of Earth Probably Did Not Contain ____