PTJ07.S3.Q11 - Feathers recently taken from seabirds stuffed

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  BlindReviewer Alum Member

  May 2019 855 karma

  Then conclusion that there was more mercury in fish in the 1880s than today is supported by two sources of data -- the amount of mercury in bird's feathers today, and the amount of mercury in stuffed birds from the 1880s. The second premise is that mercury in birds' feathers comes from the fish they consume.

  Hopefully you can see there are a few problems here -- 1) the stimulus never says fish are the ONLY place birds can get mercury from 2) we don't know if stuffed birds are the same as living birds from the 1880s and 3) even if birds did get all their mercury from fish, we don't know if they ate fish at the same rate as birds from the 1880s. Whenever there's a comparison between two sets, and a conclusion is drawn, you have to wonder about the variables that exist in comparing those two sets.

  The answer, E, draws on the 2nd assumption I pointed out. If stuffed birds have less mercury because of some preservation technique, then they aren't accurate measures of birds in the 1880s.