Years ago gardeners who grew water plants sometimes dumped their
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08 Mar 2024, 18:41
Years ago gardeners who grew water plants sometimes dumped their excess water hyacinths in rivers and streams. Since the water hyacinth is highly invasive, this dumping resulted in rapid spread of these plants in areas outside their native range. Clearly, the water hyacinth would not now be a nuisance in these areas had gardeners disposed of their excess plants more responsibly.
The conclusion of the argument is the following:
the water hyacinth would not now be a nuisance in these areas had gardeners disposed of their excess plants more responsibly
The support for the conclusion is the following:
Years ago gardeners who grew water plants sometimes dumped their excess water hyacinths in rivers and streams. Since the water hyacinth is highly invasive, this dumping resulted in rapid spread of these plants in areas outside their native range.
We see that the author has reasoned that, since gardeners caused the rapid spread of water hyacinths by dumping the plants, the water hyacinth would not be a nuisance if the gardeners hadn't dumped the plants.
One thing that may jump out at us is that the fact that the gardeners caused the problem doesn't mean that it wouldn't have occurred if they hadn't caused it. After all, it could have occurred in some other way. So, it's possible that the correct answer will be related to this issue with the argument.
Which of the following, if true, most seriously weakens the argument above?
The correct answer will show that, even though the evidence is true, the conclusion doesn't necessarily follow from it.
A) Water hyacinths are closely related to bog plants that are not highly invasive.
This choice has no effect on the argument.
The passage states as fact that "the water hyacinth is highly invasive," and this choice doesn't change that fact.
Eliminate.
B) In its native range, the water hyacinth's spread is kept in check by animals that feed on the plants.
This choice has no effect on the argument. After all, the argument is about the effect of dumping water hyacinths "outside their native range," not "in its native range."
So, regardless of how it's kept in check in its native range, dumping appears to have caused it to spread, and the support that that fact provides for the conclusion remains the same.
Eliminate.
C) Strong winds can pick up water hyacinths, which have no roots, and carry them many miles from where they had been growing.
The author has reasoned that, since water hyacinths were spread outside their native range by dumping, "the water hyacinth would not now be a nuisance in these areas" outside its native range if the dumping had not occurred.
So, what if this choice is true?
If this choice is true, then we have reason to doubt the conclusion. After all, if strong winds can carry water hyacinths many miles, then even if the gardeners had not dumped water hyacinths outside their native range, the winds might have carried them outside their native range.
In that case, it would not be correct to conclude that "the water hyacinth would not now be a nuisance in these areas" outside its native range if the dumping had not occurred because it could still have become a nuisance even if dumping had not occurred if the wind blew it outside its native range.
In other words, this choice weakens the case for the conclusion by showing that water hyacinths could have spread in another way.
So, this choice weakens the argument.
Keep.
D) Many gardeners who grow water plants now refuse to grow water hyacinths, knowing that these plants are invasive.
This choice about "now" doesn't change what the argument is about, which is dumping that occurred in the past.
In other words, regardless of what gardeners do now, it could still be the case that the water hyacinth would not be a nuisance if gardeners had not dumped it in the past.
Eliminate.
E) Although water hyacinths are native to tropical regions, they grow well outside these regions.
This choice is related to the argument in that it follows from what the argument says. After all, if water hyacinths have "spread" and become a "nuisance," then it follows that water hyacinths grow well outside their native regions.
At the same time, we don't need a conclusion that follows from what the argument says. We need a weakener.
Eliminate.
Correct answer: C