In Yasukawa's month-long study

Answer choices

1. A

   Correct84% picked this

   Yasukawa compared the survival chances of two different species of blackbirds, a larger and a small species, rather than of different sizes

   Why this is right

   This allows us to say, "Critic, your objection isn't (necessarily) valid." You're worried that the smaller birds were just the younger birds and that's why they were more likely to survive. But Yasukawa wasn't looking at just one population of blackbirds. He was comparing a group of Carolina Blackbirds to a group of Australian Blackbirds. Carolina blackbirds are a bigger species of bird than Australian blackbirds are. We can't say that the smaller birds were better able to survive because they're smaller. After all, a young Carolina blackbird is still bigger than a older Australian blackbird. So shorter ≠ younger for this data set.

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

   84%
2. B

   No Impact2% picked this

   Yasukawa examined blackbirds in their natural habitat rather than

   In order for the critic to say, "The real reason the shorter ones were more likely to survive was their age, not their size", does she need to think that this experiment took place in captivity? No, she could make that objection whether the data was collected in a lab or in the field.

   2%
3. C

   Helps Critic, if anything4% picked this

   Yasukawa did not compare the survival chances of blackbirds with those of other

   If Yasukawa found that there was a correlation between shorter / more likely to survive in other kinds of birds in addition to blackbirds, that would hurt the critic. That would bolster the idea that size does impact survival. The fact that Yasukawa only saw this correlation within blackbirds would help the critic argue that this was just a symptom of age, not size.

   4%
4. D

   Helps Critic7% picked this

   Yasukawa noted that the larger blackbirds had more success in fights than did

   The critic wants to say, "The real reason the shorter ones were more likely to survive was their age, not their small size". If the larger birds had more success in fights, that would help the critic argue that "small size is not the reason for higher survival rates." Yasukawa was arguing that being smaller helps your survival chances.

   7%
5. E

   No Impact3% picked this

   Yasukawa noted that the larger blackbirds tended to have more firmly established social hierarchies than

   The fact that larger birds have more firmly established social hierarchies doesn't have any common sense link to likelihood of surviving. It doesn't help us assess whether the smaller ones were more likely to survive because they were younger or because they were smaller.

   3%