By detailing the percentages of gases in the air we breathe, the lecturer instructs on respiration and the need for oxygen. He also recaps the structure of alveoli in our lungs and how they interact to allow gas exchange with our blood.

Hear how carbon functions on our earth and the purpose it serves. The carbon cycle is illustrated with narration for your junior high or high school biologists. Global temperature increase is also included, though the clip cuts off...