[单项选择] Influenced by movies and popular novels, most people see sharks as people-eating monsters. This is far from the truth. Every year, a few types of sharks injure about 100 people worldwide and kill about 25. Most attacks are by great white sharks, which often feed on sea lions and other marine mammals (海洋哺乳动物). They sometimes mistake human swimmers for their normal prey, especially if they are wearing black wet suits. If you are a typical ocean-goer, your chances of being killed by an unprovoked attack by a shark are about 1 in 100 million. You are more likely to be killed by a pig than a shark and thou sands of times more likely to get killed when you drive a car. Sharks help save human lives. In addition to providing people with food, they are helping us learn how to fight cancer, bacteria (细菌), and viruses. Sharks are very healthy and have aging processes similar to ours. Their highly effective immune system allows wounds to heal quickly without becoming infected, and their blo
A. friends
B. enemies
C. food
D. suits