Bài ôn tập số 1

Some pet owners claim that, before an earthquake, their pets become restless and agitated, whine for no reason, or simply try to run away. This has led many people to believe that animals have an additional sense that warns them of these upcoming events. This, however, is not a new idea. In fact, the belief that animals can predict earthquakes appears as far as the 4^th century B.C.,.in the historical records of the Greek city of Helike. These records state that animals abandoned the city all at once just days before a major earthquake destroyed it, causing people to believe that the animals had been forewarned of the event. Given the existence of these types of anecdotal stories one might begin to wonder if animals could possibly have a sixth sense that helps them predict seismic activity. Well, if we’re to believe the U.S Geological Survey – the agency charged with studying Earth – the answer is no. According to their studies, no credible evidence has been discovered to show that animals are able to predict earthquakes at all. But if this is correct, what explains the regular reports of strange behaviour before earthquakes? One theory is that animals simply have more highly effective senses than humans. With their superior hearing, dogs and cats – in addition to other animals – can perceive the infrasonic sounds produced by tectonic movement over long distances. However, without understanding what the sound is , they simply want to flee from it, causing them to act much differently than they normally would

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