In deep temperate lakes

Answer choices

1. A

   Out of Scope: ease of catching19% picked this

   The ease with which lake trout can be caught by anglers varies with the time of year

   Nothing in the argument is talking about the ease / difficulty of catching trout. We might think to ourselves, "Can't we infer this? If the trout are closer to the top in the winter and closer to the bottom in the summer, then isn't it easier to catch trout at certain times / temperatures than at others?' 1) we don't know if it's easier or harder to catch trout at the top vs. bottom of the lake 2) we don't know if the water temperature of the lake actually changes. The argument was never talking about the overall temperature of the water. It was only talking about the distribution of temperatures within the water. Overall, we want to look out for this type of trap answer on Necessary Assumption -- it's baiting us into picking it because it sounds like a "true" idea we could derive from somewhere in the paragraph. But the correct answer shouldn't feel like "an Inference we can derive from the premises". It should feel like "a thought the author must have been having in order to arrive at her conclusion".

   19%
2. B

   Out of Scope: dense / heavy2% picked this

   Cold water is denser, and therefore heavier, than relatively

   Nothing in this paragraph deals with the density or weight of water. If we negated this and said that cold water is not denser than warmer water, it would change nothing in the argument. The seasonal change in distribution of cold water occurs every year, regardless of which type of water is denser or heavier.

   2%
3. C

   Too Strong: exclusively4% picked this

   Lake trout are found exclusively in deep

   This luring us with their classic bait of, "Only Thing Mentioned = Only Thing". Just because this paragraph only mentions lake trout in deep temperate lakes doesn't mean we get to say that lake trout are only found in deep temperate lakes. If we negate this and say that, "Lake trout are also found in other types of lakes", that wouldn't hurt this argument at all.

   4%
4. D

   Out of Scope: feeding habits8% picked this

   Lake trout do not alter their feeding habits from one part of the

   Given that the author is telling us that trout live at the top of the lake for part of the year and at the bottom of the lake for the other part of the year, it seems very likely that the author might believe that lake trout do alter their feeding habits. There are probably different things to eat at the top of the lake than at the bottom. But not only is this answer contradicting how we might guess the author would be thinking, it's also just not important to the logic. This argument is just about instructing anglers whether to aim for the top of the lake or the bottom of the lake. Whether trout's feeding habits stay the same or not, it's still the case that they're living near the top for half the year and near the bottom for half.

   8%
5. E

   Correct68% picked this

   In deep temperate lakes that have ice residues on the surface, late-winter "turn-over" has

   Why this is right

   This is saying, "if the lake is still partially iced over in the late-winter, then the water hasn't switched yet (turnover has not yet occurred). The coldest water is still on top of the lake, so that's where the trout are." That's definitely what our author seemed to believe, since he's recommending that anglers aim for the top of the lake. If we negate this, it would say, "in deep temperate lakes with ice on the surface, turnover has occurred." That would mean that the cold water has now shifted to the bottom of the lake, and since the trout go where the coldest water is, the trout would have shifted to their summer haunts. Since negating this would badly weaken the argument (in this case, it would almost flat-out contradict the conclusion), it's the correct answer.

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

   68%