The atmosphere of early Earth did not include:

A) carbon dioxide.
B) water vapor.
C) carbon monoxide.
D) nitrogen.
E) hydrogen.

Carbon Monoxide

A colorless, odorless, and toxic gas produced by incomplete combustion of carbon-containing materials, capable of binding with hemoglobin and reducing blood's oxygen-carrying capacity.

Water Vapor

The gaseous phase of water, present in the atmosphere and an important part of the Earth's water cycle and weather.

Carbon Dioxide

A colorless, odorless gas produced by burning carbon and organic compounds and by respiration. It is naturally present in air and is absorbed by plants in photosynthesis.