The secondary atmosphere of the earth was composed mainly of carbon dioxide and nitrogen volcanic gases nitrogen and oxygen carbon dioxide and oxygen flag this question question 2 1 pts before the evolution of life produced the process of photosynthesis, small amounts of oxygen were added to the earth's atmosphere by the process of

A) The secondary atmosphere of the earth was composed mainly of volcanic gasses. Volcanic eruptions are caused by the dissolved gasses found in the magma. These volcanis eruptions release volcanic gasses in the atmosphere. The most abundant gas is water vapor which is very harmless. The other gases include carbon dioxide, hydrogen sulfide and sulfur dioxide.

B) Before evolution small amounts of oxygen were added to the atmosphere by the process of photodissociation of water vapor. Photodissociation of water vapor is the process through which water vapor molecules are broken down to form new molecules which are oxygen and hydrogen molecules. This process helped to increase the level of oxygen.