Carotid artery disease is caused by a buildup of plaques in arteries that deliver blood to your brain. Plaques are clumps of cholesterol, calcium, fibrous tissue and other cellular debris that gather at microscopic injury sites within the artery. This process is called atherosclerosis.
Great white sharks may not be the world's biggest sharks, since that title goes to the whale shark, but they are the planet's largest known predatory fish. Whale sharks and great whites couldn't be more different in temperament.
Whale Shark. Photograph by Brian J. Skerry. The largest fish in the sea, the whale shark can reach lengths of 40 feet (12 meters) or more. The gentle giants are filter feeders, swimming with their wide mouths open to collect plankton and small fish.