Question

) The most important source of the free oxygen in our atmosphere is: A) green plants that carry on photosynthesis. B) deforestation. C) volcanic degassing. D) the dissociation of water vapor in the upper atmosphere.

Answer 1

Answer: Option A) green plants that carry on photosynthesis

Explanation:

Photosynthesis is the process by which green plants generate their food from simple inorganic molecules like atmospheric carbon dioxide and water in the presence of sunlight trapped by chlorophyll, giving off free molecules of oxygen gas as by-product into the atmosphere.

The equation is shown below:

6CO2 + 6H2O --> C6H12O6 + 6O2

Thus, everytime plants undergo photosynthesis, they release 6 moles of free oxygen gas into the atmosphere.