I think its C) Released by the Geo-sphere because volcanos give off the same exact gases and have been around long enough to give off enough gas to create an atmosphere.
The importance is that so you don’t have any greenhouse gases that could practically harm our earth in the present world
The movement of air through Earth's -- or any planet's -- atmosphere is called wind, and the main cause of Earth's winds is uneven heating by the sun. This uneven heating causes changes of atmospheric pressure, and winds blow from regions with high pressure to those with low pressure.
