Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:
A recent investigation by scientists at the U.S. Geological Survey shows that strange animal behavior might help predict earthquakes. Investigators found such occurrences within a ten – kilometer radius of the epicenter of a fairly recent quake. Some birds screeched and flew about wildly; dogs yelped and ran around uncontrollably. Scientists believed that animals can perceive environmental changes several hours or even days before the mishap. Animals were noted as being restless for several weeks before a Tashkent, Uzbekistan, earthquake. An hour before the disaster, domestic animals refused go to indoors, and dogs howled and barked furiously. In 1960, an earthquake struck Agadir in Morocco. Survivors recall that stray animals, including dogs, were seen streaming out of town before the earthquake. In a safari zoo near San Francisco, llamas would not eat the evening before a 1979 quake, and they ran around wildly all night. Unusual animal behavior preceding earthquakes has been noted for centuries. British Admiral Robert Fitzroy reported huge flocks of screaming seabirds over Concepcion, Chile, in 1835. An hour and a half later, dogs were seen fleeing, and ten minutes later the town was destroyed. Similar stories of chickens running around in apparent states of panic, horses trembling, and dogs barking incessantly were recorded throughout the eighteenth and nineteenth centuries by survivors of earthquakes destruction in India, Yugoslavia, Peru, Mexico, and the United States. In 1976, after monitoring bizarre animal behavior, the Chinese predicted a devastating earthquake. Although hundreds of thousands of people were killed, the government was able to evacuate millions of other people and thus keep the death toll at a lower level.
Question: The author implies that animals are aware of an impending earthquake because
