PrepTest 145, Section 2, Question 25
Among small- to medium-sized marine mammals such as(43 more words not shown)
If the information above is(11 more words not shown)
- ADolphins can dive(17 more words not shown)
- BWeddell seals can(19 more words not shown)
- CWeddell seals can(17 more words not shown)
- DNorthern fur seals(19 more words not shown)
- ENorthern fur seals(21 more words not shown)
Reading the argument
We have two comparisons, not a complete ranking.
Dolphins can go deeper than northern fur seals. Elephant seals can stay submerged longer than Weddell seals, which means elephant seals can also go deeper under the rule we're given. We don't yet know how the dolphin-and-northern-fur-seal pair fits with the elephant-and-Weddell pair.
What we’re looking for
The task is 'could be true EXCEPT,' so four answers can fit the facts and one cannot. Treat each answer as a proposed addition. Convert any longer-submersion statement into its depth consequence, then see whether we can arrange all four animals consistently. We should accept the stated time-and-depth rule rather than invent an exception based on, say, one animal swimming faster.
Working the answers
- A
This can work. From deepest to shallowest, one possible order is elephant seals, dolphins, Weddell seals, northern fur seals. Dolphins go less deep than elephant seals but deeper than Weddell seals, as A requires. Dolphins also go deeper than northern fur seals, and elephant seals go deeper than Weddell seals, preserving both original comparisons. Their maximum submersion times could follow the same order, satisfying the stated time-and-depth rule too.
- B
This can work as well. Longer submersion for Weddell seals than northern fur seals requires Weddell seals to reach greater depths. One possible depth order is dolphins, elephant seals, Weddell seals, northern fur seals. It puts dolphins deeper than Weddell seals and Weddell seals deeper than northern fur seals without disturbing either original comparison. Submersion times can also be assigned in that order.
- C
Put elephant seals deepest, then Weddell seals, then dolphins, then northern fur seals. Weddell seals now go deeper than dolphins. They could also stay submerged longer than northern fur seals, with their greater depth fitting the stated rule. Elephant seals still go deeper than Weddell seals, and dolphins still go deeper than northern fur seals. So C could be true.
- DCorrect
The first half requires northern fur seals to go deeper than elephant seals, because it says they can stay submerged longer. Add the original facts and we get this order: dolphins deeper than northern fur seals, northern fur seals deeper than elephant seals, and elephant seals deeper than Weddell seals.
That puts dolphins deeper than Weddell seals. But the second half of D says Weddell seals can go deeper than dolphins. We cannot satisfy both. Following the comparisons would require dolphins to be deeper than Weddell seals and Weddell seals to be deeper than dolphins. D is the one proposed arrangement that cannot be true.
- E
This can work. The longer submersion time requires northern fur seals to go deeper than Weddell seals, while E also puts elephant seals deeper than northern fur seals. One possible order is dolphins, elephant seals, northern fur seals, Weddell seals. Both original comparisons still hold, and submersion times can follow the same order. Unlike D, this arrangement never forces two animals to outrank each other.
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