The surface area of a human lung is equal to a tennis court. To more efficiently oxygenate the blood, the lungs are filled with thousands of branching bronchi and tiny, grape-like alveoli and microscopic capillaries to keep you properly oxygenated.
 | Make Your Own Fudge Brownie Chocolate Protein Bars |
 | How to Motivate Yourself When You Feel Lazy |
 | Happiness Is An Inside Job |
 | 14 Surprising Facts About Mangos |
