Question

Which explains why oxygen was absent from Earth’s early atmosphere?

Excess heat converted atmospheric oxygen into other gases

Oxygen chemically combined with newly formed rocks. Photosynthesizing organisms such as plants had not yet appeared. Volcanic gases suppressed the natural production of oxygen

Answer 1

Oxygen chemically combined with newly formed rocks

Step-by-step explanation:

At the start of the universe, oxygen was produced as by products of photosynthesis by cyanobacteria. Rocks contained a mineral called olivine that combined rapidly with oxygen in the presence of water thereby removing oxygen from the earth's atmosphere.

However, as the earth crust evolved to a composition more like what we have today, olivine virtually disappeared. In the absence of that mineral to react with water and consume oxygen, the gas was finally allowed to accumulate in the earth atmosphere. Oceans eventually became saturated, and oxygen crossed into the atmosphere.

Answer 2

The reason why oxygen was absent from Earth's early atmosphere is excess heat converted atmospheric oxygen into other gases. Therefore, the correct answer to the above question is option A.

Step-by-step explanation:

Oxygen is a most abundant gas of the atmosphere. Oxygen occupies 21% of the total share of the gases that is present in the atmosphere of earth. All the living animals and aquatic animals take oxygen for their life to happen.

Green plants are the only source of conversion of carbon dioxide into oxygen. Oxygen is carried in human body by the blood throughout the whole body. Due to the presence of oxygen in air are very animals and plants living on the earth