The respiratory system includes the nose, throat, larynx, trachea, bronchi, and lungs. Discover how the respiratory system supplies blood with necessary oxygen and relieves it of the waste product carbon dioxide.
You breathe in and out anywhere from 15 to 25 times per minute without even thinking about it -- it just happens naturally. Learn all about your lungs, various conditions and diseases, and what makes the breath of life so crucial. See more »
In the movie "WaterWorld," Kevin Costner's character has a mutation that gives him gills behind the ears. Could a mutation allow people to swim in the water just like fish --without having to use any sort of scuba equipment? See more »