The male sage grouse has air sacs

Answer choices

1. A

   Opposite (if anything)2% picked this

   Some female sage grouse mate with unhealthy male

   The fact that some females will mate with unhealthy males, if anything, undermines the author's story that females are investigating whether a potential mate is healthy.

   2%
2. B

   Unclear Impact17% picked this

   When diseased male sage grouse were treated with antibiotics, they were not selected by female sage grouse

   It's hard to interpret this because it's not clear whether the males' inflated air sac display looked like that of a sick male or that of a male who was healthy again from antibiotics. We can't really tell whether the female rejected them when they still look diseased (which would fit the author's hypothesis) or whether she rejected them even once she were back to normal (which would undermine the author's hypothesis).

   17%
3. C

   No Impact2% picked this

   Some healthy male sage grouse do not inflate their air sacs as part of

   This is incredibly weak (so unlikely to be correct on Str, Wkn, Paradox) and also off topic, since it's talking about males that don't inflate their air sacs. It could be relevant if we knew these males were uninterested in mating with females. That would sort of be a "no cause, no effect" strengthener (males who have no interest in mating with females DON'T bother to inflate their air sacs for the health inspection). But this is saying there's at least one male that does want to mate but doesn't inflate its air sac. That doesn't help us figure out why the males that DO inflate their air sacs are doing so.

   2%
4. D

   Correct79% picked this

   Male sage grouse are prone to parasitic infections that exhibit symptoms visible on the

   Why this is right

   If male sage grouse are prone to parasitic infections that exhibit symptoms visible on their air sacs, then a visible cue exists that females can use to judge a male's health based on the appearance of the air sacs. This provides a direct link that supports the hypothesis that the air sac display helps females select healthy mates.

   Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.

   79%
5. E

   No Impact1% picked this

   The sage grouse is commonly afflicted with a strain of malaria that tends to change as the organism

   The fact that sage grouse are commonly afflicted with a particular strain of malaria doesn't tell us anything about whether the malaria presents in the air sacs, or whether females would be able to ascertain any health information by looking at inflated air sacs.

   1%