Exposure to certain chemicals commonly used in elementary schools as cleaners or pesticides causes allergic reactions in some children. Elementary school nurses in Renston report that the proportion of schoolchildren sent to them for treatment of allergic reactions to those chemicals has increased significantly over the past ten years. Therefore, either Renston's schoolchildren have been exposed to greater quantities of the chemicals, or they are more sensitive to them than schoolchildren were ten years ago.
Which of the following is an assumption on which the argument depends?
(A) The number of school nurses employed by Renston's elementary schools has not decreased over the past ten years.
(B) Children who are allergic to the chemicals are no more likely than other children to have allergies to other substances.
(C) Children who have allergic reactions to the chemicals are not more likely to be sent to a school nurse now than they were ten years ago.
(D) The chemicals are not commonly used as cleaners or pesticides in houses and apartment buildings in Renston.
(E) Children attending elementary school do not make up a larger proportion of Renston's population now than they did ten years ago.
Let’s understand the details of the argument.
1)Exposure to certain chemicals commonly used in elementary schools as cleaners or pesticides causes allergic reactions in some children.
2) Elementary school nurses in Renston report that the proportion of schoolchildren sent to them for treatment of allergic reactions to those chemicals has increased significantly over the past ten years.
Conclusion- Therefore, either Renston's schoolchildren have been exposed to greater quantities of the chemicals, or they are more sensitive to them than schoolchildren were ten years ago.
We need to find the assumption for this argument.
(A) The number of school nurses employed by Renston's elementary schools has not decreased over the past ten years.
This has no relevance to the conclusion of the argument. The conclusion is that, it is either that R’s Schoolchildren have been exposed to greater quantities of chemicals or that they have become more sensitive to chemicals than schoolchildren were ten years ago- Eliminate A
(B) Children who are allergic to the chemicals are no more likely than other children to have allergies to other substances.
The comparison is not between children who are allergic to chemicals and children who are allergic to other substances. Eliminate B
(C) Children who have allergic reactions to the chemicals are not more likely to be sent to a school nurse now than they were ten years ago.
Let’s negate this option to see whether it will impact our conclusion or not. Children who have allergic reactions to the chemicals are more likely to be sent to a school nurse now than they were ten years ago. This means that it is not that Renston's schoolchildren have been exposed to greater quantities of the chemicals, or that they are more sensitive to them than schoolchildren were ten years ago. The negation of the assumption in Option C leads to the negation of the conclusion. Option C confirms what is stated in the conclusion by stating that more school children were not sent to a school nurse now than they were ten years ago. Hence C is our assumption.
(D) The chemicals are not commonly used as cleaners or pesticides in houses and apartment buildings in Renston.
Irrelevant to the argument. Eliminate D
(E) Children attending elementary school do not make up a larger proportion of Renston's population now than they did ten years ago.
This comparison is irrelevant to the argument. Eliminate E