PrepTest 158, Section 2, Question 17
To establish a human colony on Mars would(36 more words not shown)
Which one of the following(7 more words not shown)
- AOnly if the(16 more words not shown)
- BThe cost of(14 more words not shown)
- CEarth is the(16 more words not shown)
- DNo significant benefit(8 more words not shown)
- EMars is not(13 more words not shown)
Reading the argument
Building a colony would require a lot of material. People would need places to live and equipment to support them. Getting all of that through space sounds expensive.
Does expensive mean economically impossible?
Airlines have large costs too, but charging passengers can make those costs worthwhile. Imagine a Mars resort whose visitors paid enormous sums. I'm not predicting such a business would work. It's a way to see the missing comparison: a large cost alone doesn't tell us whether the possible return can cover it.
There's also the possibility of better technology. Perhaps transportation gets cheaper over time. The argument hasn't explained why the current cost problem must remain insurmountable.
What we’re looking for
The question asks for an assumption the argument requires. My initial concerns are about treating a high expense as enough to rule out economic feasibility. The choices may identify one of those gaps or a different way the argument depends on the shipping problem. We should test what the reasoning actually needs, rather than demand one exact prediction.
Working the answers
- A
Transportation costs don't have to fall for a project to become worth undertaking. The benefits could increase, or the colony might require fewer materials. And the conclusion concerns economic feasibility, not an absolute claim that no one will ever establish a colony under any circumstances. A imposes a requirement beyond what this argument needs.
- B
Costs could decrease and still remain prohibitively high. A drop from a billion dollars to nine hundred million dollars, for example, would be a decrease without necessarily making a project feasible. The argument doesn't need to rule out every decrease in the near future; its concern is the burden that remains.
- C
Earth needn't be the only source. Materials might be available on some other planet and still be extremely costly to transport to Mars. The argument relies on the expense of moving materials through space, not on their all starting from Earth.
- D
There could be significant benefits that still weren't enough to make the colony economically feasible. A benefit and a prohibitive cost can coexist. Saying the expense makes the project infeasible doesn't require denying every significant benefit of the project.
- ECorrect
Here's another route around the supposed obstacle: what if we get the materials on Mars? The argument moves from needing materials at the colony to the high cost of transporting them through space. It hasn't established that the necessary materials must be shipped in.
If Mars were a practical source, colonists could obtain the materials there instead of incurring the transportation burden the author treats as decisive. The argument therefore needs to rule out that option. E does so without insisting that Earth is the only off-planet source or that costs can never change.
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