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 air that people breathe is a mixture that contains primarily oxygen and nitrogen. The nitrogen generally makes up approximately 78%, while oxygen makes up 21%. Other gases, including carbon dioxide, hydrogen, helium, argon, and neon, make up the remainder. These gases dissolve and are carried in the blood.