Gases found in primitive atmosphere are

Name the gases that were found in primitive earth's atmosphere.

The primitive atmosphere was reducing.

Assertion : Primitive atmosphere was formed by the lightest atoms. Reason : The primitive atmosphere was reducing in nature.

According to oparin which of the following was not present in primitive atmosphere of earth

The primitive atmosphere was reducing in nature. Free oxygen was absent in the primitive atmosphere.

Which was not present in primitive atmosphere?

Which was not present in primitive atmosphere?