When the ancient fossils

Answer choices

1. A

   Strengthens4% picked this

   The unearthed land mammal is only one of several ancient land mammals that were indigenous

   This choice implies that there were several mammals, which would suggest more competition, which helps the author argue "See? There was lots of competition from mammals. So that theory is wrong."

   4%
2. B

   Correct90% picked this

   The recently discovered land mammal became extinct long before the native bird

   Why this is right

   This choice states that the newly discovered mammal went extinct long before the birds established themselves in New Zealand. It weakens the conclusion by allowing the original theory to hold—that the birds thrived due to a lack of competition with any existing mammals when their population was growing.

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

   90%
3. C

   No Impact2% picked this

   The site at which the primitive land mammal was unearthed also contains the fossils of primitive

   Finding reptiles and insects alongside mammal fossils does not affect the causality concerning bird populations and mammalian competition, leaving the conclusion unchallenged.

   2%
4. D

   No Impact3% picked this

   Countries with rich and varied native land mammal populations do not have rich and varied

   This sort of reinforces the background idea that "when there are tons of mammals, birds won't do as well". Both the author and her opponents accept this. The opponents think that NZ didn't have mammals, so that's why birds did well. The author thinks that NZ did have mammals, so there must be some other reason why NZ birds did well. We don't know if NZ ever had a rich and varied land mammal population. So this doesn't help us analyze whether NZ's bird population was ever competing with mammals.

   3%
5. E

   No Impact1% picked this

   Some other island countries that are believed to have no native land mammals in fact had indigenous land

   This refers to other island countries having unexpected land mammals and aligns with the author's evidence, slightly reinforcing it rather than undermining it. It has no substantial effect on the argument about the lack of competition leading to New Zealand's rich bird population.

   1%