Verbal Ability - Question Of The Day

Question:
Analyze the data and answer the question that follows.

There is no evidence to show that fluoride plays a role in the decline of tooth decay, it may in fact be unnecessary. The US recently conducted a survey, questioning several thousands of children and they found little difference in tooth decay among children in fluoridated and non-fluoridated communities.

Which of the following statements, if true, strengthens the argument presented above?

OPTIONS

1) Fluoride is only one of thirty-three elements essential for human beings.
2) Children like the taste of fluoridated toothpaste.
3) Dentists continue to recommend the use of fluoridated toothpaste to all their patients.
4) In places where use of fluoridated toothpaste has ceased, dental decay has decreased.
5) Rats fed for one year with 1 ppm fluoride in their water, had morphological changes to their kidneys and brains.

Solution

The author of the passage states that there is no evidence to show that fluoride is necessary. In fact according to the survey the US conducted there is no role it plays in preventing tooth decay.
Therefore to strengthen this argument we need a statement that supports the fact that fluoride is indeed unnecessary.
Options 1, 2 and 3 merely add data without strengthening the core assertion.
Option 5 offers a good point to strengthen the argument against fluoridated toothpaste but is ruled out because there is no information about this experiment, has it been replicated, what this means for human beings etc.
Option 4 provides a valid point to strengthen the argument against fluoride. This statement shows that in this case stopping use of fluoride leads to healthier teeth.
Hence, the correct answer is option 4.


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