PrepTest 130, Section 1, Question 1
Commentator: Although the present freshwater supply is adequate(42 more words not shown)
Which one of the following(7 more words not shown)
- AHumans will adapt(16 more words not shown)
- BThe total supply(8 more words not shown)
- CThe freshwater supply(11 more words not shown)
- DNo attempt to(13 more words not shown)
- ENo water conservation(15 more words not shown)
Reading the argument
More people will need more water. But will they need more than we have?
The current supply is adequate, and we can accept that population growth will greatly increase demand. Neither fact tells us how close we are to running short. Imagine that we have enough freshwater for ten times the current population. A substantial increase in population could leave us with plenty. The commentator needs the growing demand to outpace the available supply before restrictions become necessary.
What we’re looking for
That's the gap I want a required assumption to address. We aren't looking for a fact that merely sounds sensible about water conservation. We need something the commentator depends on in moving from greater demand to the need for restrictions.
Working the answers
- A
The argument doesn't depend on how people treat other natural resources after water restrictions are imposed. People might conserve water while wasting some other resource, and water restrictions could still be necessary to meet freshwater needs.
- B
The recent history of the supply doesn't settle whether future restrictions are needed. Perhaps the supply fell from ten billion gallons to nine billion; perhaps it rose to eleven billion. Either history could be consistent with today's adequate supply and tomorrow's shortage. The argument needn't assume that the supply has not diminished.
- CCorrect
This addresses another way the available supply might keep up: it could increase. If the freshwater supply grew enough to meet humanity's increased needs, why would restrictions be necessary? Greater demand alone would not establish that conclusion. The commentator therefore needs to assume that the supply will not increase sufficiently to meet those needs.
- D
Synthesizing water could make an appreciable difference without solving the entire problem. Suppose it covered ten percent of the shortfall. That would help, but restrictions could still be necessary to address the rest. The argument needs insufficient additional supply, not the complete failure of this particular way of adding supply.
- E
Past conservation efforts could have increased the water available for human use, while future demand could still outrun it. The commentator doesn't need every earlier measure to have failed. The question is whether the future supply can meet the future need.
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