What documents do I need to present to reenter the United States? If seeking to enter the United States after temporary travel abroad, you will need to present a valid, unexpired âgreen cardâ (Form I-551, Permanent Resident Card).
Brain Tour. 2. Supply lines. Your brain is nourished by one of your body's richest networks of blood vessels. With each heartbeat, arteries carry about 20 to 25 percent of your blood to your brain, where billions of cells use about 20 percent of the oxygen and fuel your blood carries. When you are thinking hard, your brain may use up to 50 percent of the fuel and oxygen.
The main function of blood vessels is to carry blood through the body. The blood carries oxygen, nutrients, and wastes that need to move around the body. There are three kinds of blood vessels: arteries, veins, and capillaries.The arteries carry blood away from the heart and transport it to the rest of the body.The blood in arteries carries oxygen and nutrients to different parts of the body.The veins carry blood the opposite direction, back to the heart from the rest of the body.he arteries carry blood away from the heart and transport it to the rest of the body. The blood in arteries carries oxygen and nutrients to different parts of the body. The veins carry blood the opposite direction, back to the heart from the rest of the body.