填空题 Recently, a group of researchers from Tokyo developed a device that allows them to identify individuals of the endangered Ganges River dolphin species. Ganges River dolphins are rare in that, unlike the majority of their counterparts, they live in fresh water rivers and lakes rather than salt water oceans. The species is blind and uses clicks to send out sonar pulses for guidance and to find food. The Tokyo researchers' new underwater acoustic device measures these pulses, which are as unique as a human fingerprint, thus allowing the identification and tracking of individual dolphins. Scientists estimate that, in the last few decades, the number of Ganges River dolphins has dropped by 50 percent due to a lethal combination of fishing nets, hunters, pollution, and human construction. With this new technology, scientists hope to get a better idea of how many of these dolphins still exist, as well as their migration patterns and feeding habits. In turn, this information may help scientists protect and conserve this unique species.
多选题 The passage suggests that Ganges River dolphins exhibit which of the following characteristics?
  • A. an ability to navigate waterways without using sight
  • B. an ability to live in freshwater environments
  • C. a tolerance for human interaction
【正确答案】 A、B
【答案解析】The passage states that the Ganges River dolphins are blind, therefore they are able to navigate without sight. Also, they live in fresh-water rivers and lakes. Human contact is said to have caused a 50 percent decline in Ganges River dolphin numbers, so they do not exhibit a tolerance for human interaction.
填空题 Select the sentence within the paragraph that explains how scientists hope to help preserve the Ganges River dolphin.