Why+do+humans+need+to+breathe?+-+R

**//__ By Ethan W __//** **//__ 2012 __//**   **//__ How oxygen affects the body __//** Why do humans need oxygen? Well the simple answer would be to live but I am going to go more in depth. All living bodies need a constant supply of fresh air or oxygen or else bad things will happen to their bodies. Within seconds of having no air the body will die or in human case suffer irreversible brain damage and or die. Some things (species of animals and plants) are much more sensitive to lack of air than others. **//__Figure 1: This is a diagram of blood and oxygen flow through the heart.__//**
 * //__ Why do humans need oxygen? __//**

While breathing the body will accumulate waste. In this case waste is carbon dioxide. The body has get rid of this waste. The process of getting rid of this waste is called respiration or breathing. During respiration the body expels the carbon dioxide (which in solid form is dry ice) and sucks in fresh oxygen.
 * //__ Oxygen __//**

**//__ Earth and Oxygen __//** Oxygen is a very is one of the most if not the most important gas on earth. Oxygen is the most abundant element on Earth. Humans need 4% oxygen per day. Without oxygen human tissue will die.

> **//__Figure 2: Oxygen can be used for medical purposes__//**
 * [[image:oxygen bear.jpg width="435" height="364"]]
 * ** Carbon Dioxide ** : a colorless incombustible gas, CO2 formed during
 * ** Carbon Dioxide ** : a colorless incombustible gas, CO2 formed during


 * ** Oxygen ** : a colorless odorless reactive gas the chemical element of atomic bomb number 8 and the life supporting component of air.


 * Respiration ** : The action of breathing.

Citations > Encyclopædia Britannica, Inc., 2012. Web. 24 Sept. 2012
 * Mark Lambert, The Lungs and Breathing, Englewood Cliffs, NJ Silver Burdett press 1988
 * "**Oxygen.**" //Compton's by Britannica//. //Encyclopedia Britannica Online School Edition//.
 * Oxygen" 01 July 2009. HowStuffWorks.com.  27 September 2012.
 * Whittemore, Susan and Denton A. Clooney. Makers of The respiratory system. Philadelphia : Chelsea House Publishers, c 2004