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Australian researchers have discovered electroreceptors (sensory organs designed to respond to electrical fields) clustered at the tip of the spiny anteater's snout. The researchers made this discovery by exposing small areas of the snout to extremely weak electrical fields and recording the transmission of resulting nervous activity to the brain. While it is true that tactile receptors, another kind of sensory organ on the anteater's snout, can also respond to electrical stimuli, such receptors do so only in response to electrical field strengths about 1,000 times greater than those known to excite electroreceptors.

Having discovered the electroreceptors, researchers are now investigating how anteaters utilize such a sophisticated sensory system. In one behavioral experiment, researchers successfully trained an anteater to distinguish between two troughs of water, one with a weak electrical field and the other with none. Such evidence is consistent with researchers' hypothesis that anteaters use electroreceptors to detect electrical signals given off by prey; however, researchers as yet have been unable to detect electrical signals emanating from termite mounds, where the favorite food of anteaters live. Still, researchers have observed anteaters breaking into a nest of ants at an oblique angle and quickly locating nesting chambers. This ability to quickly locate unseen prey suggests, according to the researchers, that the anteaters were using their electroreceptors to locate the nesting chambers.

                                                                                                                                                                                                   1.Which of the following can be inferred about the experiment described in the first paragraph?

• AResearchers had difficulty verifying the existence of electroreceptors in the anteater because electroreceptors respond to such a narrow range of electrical field strengths.
• BResearchers found that the level of nervous activity in the anteater’s brain increased dramatically as the strength of the electrical stimulus was increased.
• CResearchers found that some areas of the anteater’s snout were not sensitive to a weak electrical stimulus.
• DResearchers found that the anteater’s tactile receptors were more easily excited by a strong electrical stimulus than were the electroreceptors.
• EResearchers tested small areas of the anteater’s snout in order to ensure that only electroreceptors were responding to the stimulus.
• 2.The passage suggests that the researchers mentioned in the second paragraph who observed anteaters break into a nest of ants would most likely agree with which of the following statements?
• • AThe event they observed provides conclusive evidence that anteaters use their electroreceptors to locate unseen prey.
  • BThe event they observed was atypical and may not reflect the usual hunting practices of anteaters.
  • CIt is likely that the anteaters located the ants’ nesting chambers without the assistance of electroreceptors.
  • DAnteaters possess a very simple sensory system for use in locating prey.
  • EThe speed with which the anteaters located their prey is greater than what might be expected on the basis of chance alone.
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  • 3.Which of the following, if true, would most strengthen the hypothesis mentioned in highlight text?
    
  A  Researchers are able to train anteaters to break into an underground chamber that is emitting a strong electrical        signal.B  Researchers are able to detect a weak electrical signal emanating from the nesting chamber of an ant colony.C  Anteaters are observed taking increasingly longer amounts of time to locate the nesting chambers of ants.D  Anteaters are observed using various angles to break into nests of ants.E  Anteaters are observed using the same angle used with nests of ants to break into the nests of other types of prey.