Passage 3

Questions 11 to 15 are based on the following passage:

There are more species(种类）of beetles(甲虫）than any other form of life. About 380,000 species of beetles are known to exist, and more are discovered all the time. (79) There are several theories about why there are so many beetles, but evidence shows that beetles have the lowest extinction rate of any animal ever.

One of the reasons beetles survive so well is their body design. Most beetle species have two pairs of wings. The front pair of a beetle’s wings are hard and thick. These project he rear set of wings and the beetle’s stomach region. They are not used for flying. Indeed, some species of beetles have lost the ability to fly, but they are still equipped with front wings.

Beetles can also eat a wide range of foods. Beetle species live all over the world, and they have many different types of food available to them. Most beetles are omnivores. That means they eat both plants and animals. The mixed diets help beetles adapt to many different environments.

Finally, beetles are good at moving quickly over long distances. Any change in an animal’s environment can be dangerous to it, but some species can avoid dangerous environment changes by migrating to a new place. Research shows that beetles respond quickly to shifts in temperature. They can migrate to safer environments.

Beetles’ bodies and habits help give them an edge over other creatures. (80) They are unlikely to die out. As a result, beetles make up nearly one quarter of all animal species. There are more types of beetles on earth than there are types of plants. Some types of beetles that exist today were around during the Permian period of history, 284 million years ago. Beetles, clearly, are here to stay.