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#11 - Feathers recently taken from seabirds stuffed and

danielle23
LSAT Apprentice
 
Posts: 10
Joined: Tue May 30, 2017 9:33 pm
Points: 10

Hello,

Could someone give me further assistance on why #11 is E and not A?

Thank you,

Danielle
Ricky_Hutchens
PowerScore Staff
PowerScore Staff
 
Posts: 59
Joined: Mon Oct 12, 2015 2:07 pm
Points: 41

I danielle,

Let's break this down. The argument is:

1. living birds have twice as much mercury in their feathers than birds stuffed and preserved in the 1880s
2. mercury in feathers comes from the fish the bird eats
C: therefore, fish had less mercury 100 years ago

Now, let's start with choice E. If the process used in the 1880s to preserve the birds decreased the mercury in the feathers, then we would naturally expect those feathers to have less mercury than birds living now because the living birds had not been preserved and thus still have all of the mercury in their feathers. E gives us an alternative explanation for what we see. Therefore, the argument must assume that this is not the case or else the argument would be weakened. So we must assume E for the argument to hold.

Now, let's consider choice A. It says that birds in the 1880s ate less fish than birds today. If that's the case, then we would expect there to be less mercury in the feathers from the 1880s. If the argument assumed this, then its conclusion wouldn't make any sense because we would have an alternative explanation that would undermine the argument's conclusion. So the argument must be assuming that A is false, not true. If A said, "the proportion of a seabird's diet consisting of fish was as high," then A would be correct.

Hope that helps.
danielle23
LSAT Apprentice
 
Posts: 10
Joined: Tue May 30, 2017 9:33 pm
Points: 10

Okay! That makes sense now.

Thank you very much!