Blood vessels (veh-suls): The system of flexible tubes—arteries, capillaries and veins—that carries blood through the body. Oxygen and nutrients are delivered by arteries to tiny, thin-walled capillaries that feed them to cells and pick up waste material, including carbon dioxide. Capillaries pass the waste to veins, which take the blood back to the heart and lungs, where carbon dioxide is let out through your breath as you exhale.
"When going out for fast food, I used to get the large-size value meal. Now, I satisfy a craving by ordering just one item: a small order of fries or a six-piece box of chicken nuggets. So far, I've shaved off 16 pounds in seven weeks, and I'm on track to being thinner than my high school self for my 10-year reunion later this year." —Miranda Jarrell, Birmingham, AL
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