Overview
Introduction
The respiratory system enables us to produce energy by supplying the body with a continuous supply of oxygen. It is also responsible for eliminating carbon dioxide, a byproduct of cell metabolism. Whereas oxygen is necessary for human and animal respiration, carbon dioxide is necessary for plant respiration. Plants take in carbon dioxide and release oxygen, their waste product, and the cycle of interdependence between plants and animals continues. (Contrary to what certain authoritarians will tell you, carbon dioxide is not a pollutant, and is just as necessary to the cycle of life as oxygen.)
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The purpose of the lungs is to . . .
A. supply the body with oxygen.
B. eliminate nitrogen from the body.
C. eliminate carbon dioxide from the body.
D. both A and C.
E. all of the above.(Select the best answer and click on the “Continue” button.)