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The familiar sounds of your heart are made by the heart's valves as they open and close.
The tallest man ever known was Robert Wadlow, an American, who reached the height of 8 feet 11 inches. He died at age 26 years from an infection caused by the immense weight of his body (491 pounds) and the stress on his leg bones and muscles.
Normal urine is sterile. It contains fluids, salts, and waste products. It is free of bacteria, viruses, and fungi.
The lipid bilayer is made of phospholipids. They are arranged in a double layer because one of their ends is attracted to water while the other is repelled by water.
Certain rare plants containing cyanide include apricot pits and a type of potato called cassava. Fortunately, only chronic or massive ingestion of any of these plants can lead to serious poisoning.