When so many oysters died

Answer choices

1. A

   No Impact3% picked this

   The increase in water temperature has slowed in the years since the

   Water temp was thought to be a cause at first, but it was determined that TBT was the cause. So we wouldn't really be able to use a story line about water temperature to explain the low oyster population.

   3%
2. B

   No Impact10% picked this

   Native oysters rely on different sources of food than do the barnacles that live on

   If native oysters and barnacles relied on the same food source, then we could potentially say that an uptick in barnacles could mean that there's not enough food left for oyster populations to grow. But this answer says they rely on different sources of food, so it has no impact.

   10%
3. C

   Correct75% picked this

   TBT also killed imported varieties of oysters that flourish at the expense of native oysters now that

   Why this is right

   Since TBT was previously killing imported oysters, now that there's no TBT, we're not killing these imported oysters. Does having these imported oysters around give us a way to explain why the native populations aren't coming back? Yes, because it says that imported oysters flourish at the expense of native oysters. So in the post-TBT warm waters near Britain, we would expect to see populations of imported oysters thriving and populations of native oysters shrinking / being suppressed. This is an example of the TBT-ban legislation having an indirect effect on the endangered oysters: TBT-ban → way less TBT → more imported oysters -> suppressed native oysters

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

   75%
4. D

   Out of Scope: other chemicals Opposite3% picked this

   Other chemicals that are used to remove barnacles from the hulls of boats seem to have little effect

   We're not really concerned with other barnacle-removing chemicals. We only cared about TBT because it was determined to be killing our native oysters. And we're trying to explain why in the aftermath of banning TBT we still don't see the native oysters coming back. We might have thought to ourselves, "Maybe after they banned TBT, ships started using a different chemical to get barnacles off the hulls of boats, and those new chemicals are hurting the endangered native oysters", in which case this answer choice does the opposite of what would be useful to us.

   3%
5. E

   Irrelevant Distinction9% picked this

   TBT is more deadly to oysters in colder waters than in

   Given that there isn't TBT in the water anymore (basically), it doesn't matter where TBT is more deadly. It's not present, so it's not the current reason why native oyster populations are struggling.

   9%