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 dry air of the Earth's atmosphere contains 71 percent nitrogen and 28 percent oxygen. Other gases comprise the remaining 1 percent. Troposphere - people, animals and plants live in this layer. It is the lowest layer and the one in which most of the weather occurs.