Photosynthesis is crucial for life on this planet, if photosynthesis did not happen the glucose on this planet would be used up quickly ,leaving no energy in a usable form; therefore ending life on this planet.
In general, the most abundant gas in earth is oxygen, since it's one of the elements in water. However if specifically in the atmosphere, nitrogen is the most abundant gas with 78%.
There are 4 states of matter : plasma, liquid, gas and solid.
