advanced practice nurse a registered nurse having education beyond the basic nursing education and certified by a nationally recognized professional organization in a nursing specialty, or meeting other criteria established by a Board of Nursing.
Quick Answer. The air that makes up Earth's atmosphere contains 20.9 percent oxygen. This is true up to about 70,000 feet above sea level. However, above 10,000 feet, the atmosphere becomes too thin to support human life, even though its proportions do not change much. Continue Reading.
The pie chart shows the proportions of the main gases in the atmosphere. The composition of air. The two main gases are both elements and account for about 99 percent of the gases in the atmosphere. They are: 1  about 4 / 5 or 80 percent nitrogen (a relatively unreactive gas).2  about 1 / 5 or 20 percent oxygen (the gas that allows animals and plants to respire and for fuels to burn).he two main gases are both elements and account for about 99 percent of the gases in the atmosphere. They are: 1  about 4 / 5 or 80 percent nitrogen (a relatively unreactive gas).