PrepTest 101, Section 3, Question 5
Bacteria from food can survive for several days(55 more words not shown)
Which one of the following(8 more words not shown)
- AWashing plastic cutting(9 more words not shown)
- BPrevention of bacterial(16 more words not shown)
- CFood that is(16 more words not shown)
- DBacteria that penetrate(17 more words not shown)
- EWashing wooden cutting(10 more words not shown)
Reading the argument
The bacteria went into the board. Have they gone away, or have they just moved out of sight?
On the surface, the comparison sounds favorable to wood. Bacteria linger on plastic, while wood quickly draws them beneath its surface. But suppose I cut food on a wooden board, wipe away the scraps, and put the board aside. Later, bacteria that entered the wood return to the surface. The next food I cut could meet bacteria that the earlier wipe never removed. A clean surface at one moment doesn't establish a clean surface every time the board is used.
That's the first question I'd ask: can the bacteria come back out? The author needs the wood to work like a one-way passage, at least for the claim about bacteria that have entered it. Otherwise, wiping off visible food debris doesn't answer the risk from bacteria below the surface.
There's another gap worth keeping separate. The evidence concerns bacteria, while the conclusion promises to prevent the board from contaminating food. What about a different contaminant that remains despite wiping? Solving the bacteria problem wouldn't automatically settle every kind of contamination.
What we’re looking for
The question asks for an assumption the argument depends on. In plain terms, what does the author need to be true for this reasoning to work? I'd look first for the answer to the return-to-the-surface problem. We don't need an answer that repairs every gap at once; a required assumption can address one problem while leaving another unanswered.
Working the answers
- A
Why must washing plastic boards fail to remove every bacterium? The conclusion concerns whether wooden boards need washing. Washing plastic could be completely effective, partly effective, or ineffective without telling us whether bacteria return to a wooden board's surface. The author doesn't need this negative claim about washing plastic.
- B
Wooden boards could have other advantages too. Maybe someone thinks they look better or finds them easier to use. That wouldn't interfere with the author's reasoning about contamination. Saying bacterial protection is their only advantage adds a restriction the conclusion doesn't need.
- C
Cutting boards needn't be the only source of contamination. Food could also contact something contaminated elsewhere on a kitchen counter. Even if the author's recommendation about wooden boards were correct, it wouldn't establish that every other route to contamination is impossible. C reaches far beyond what the argument needs.
- DCorrect
If bacteria can reemerge, moving them below the surface hasn't removed the risk the author treats as solved. They could come back after the board has been wiped and contact food later. D blocks that possibility by keeping those bacteria beneath the surface. It addresses our main objection without proving the entire recommendation: the separate question about other contaminants still remains.
- E
Killing bacteria below the surface might make washing useful, but the author is defending not washing. We need to know why wiping is adequate even while bacteria remain in the wood. What washing would kill doesn't establish that the author can safely dispense with washing, and the argument doesn't require washing to reach those bacteria.
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