PrepTest 111, Section 3, Question 22
The folktale that claims that a rattlesnake's age(61 more words not shown)
Which one of the following(15 more words not shown)
- ARattlesnakes molt exactly(3 more words not shown)
- BThe rattles of(8 more words not shown)
- CRattlesnakes molt more(6 more words not shown)
- DThe brittleness of(13 more words not shown)
- ERattlesnakes molt as(12 more words not shown)
Reading the argument
Counting sections tells us how many times the snake molted. Does it tell us how much time has passed?
The author identifies one problem: sections can break off. An old snake might therefore have a short rattle. But removing that problem doesn't automatically turn the rattle into a clock. We still need a dependable connection between molting and age.
What if food availability changes how often the snake molts? One snake might add sections quickly while another of the same age adds them slowly. Or imagine a snake adding a section after two weeks, then not adding another for three years. Without a predictable timing pattern, two sections wouldn't tell us much about its age.
What we’re looking for
We're asked for an assumption the argument requires. I'd look for something that keeps outside circumstances from disrupting the relationship between sections and elapsed time. We don't need to choose a particular calendar interval. One section every six months could allow dating just as one section every year could, if that were the dependable pattern.
Working the answers
- A
Exactly once a year is one possible schedule, but the argument doesn't require that particular schedule. Suppose every snake added a section every six months. Counting intact sections could still indicate age. A is more specific than the reasoning needs, even though a fixed annual schedule would be helpful.
- B
Different species could have rattles that look different while their sections remained countable. Identical appearance isn't needed to connect the number of sections with time. The issue is what the count tells us, not whether every species' rattle looks alike.
- C
The argument doesn't require younger snakes to molt more often. A steady frequency at every age could also make section counts useful. Nor would every age-related change necessarily ruin the method if it followed a known schedule. C gives a particular age pattern without supplying an assumption the argument must make.
- D
The argument is already asking what would happen if the rattles weren't so brittle. Whether actual brittleness is associated with lifespan doesn't tell us how often sections form in that proposed situation. It leaves the timing problem unresolved.
- ECorrect
If food availability changed molting frequency, a snake with more sections might simply have had more food. The count alone would no longer reliably identify its age. We would need information about its feeding history too.
E removes that source of variation. It doesn't settle every possible difficulty with dating a snake, but it is something the proposed count-only method needs: scarce versus plentiful food cannot change the frequency of the event we're using to track time.
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