题目内容：
Directions: Each passage in this group is followed by questions based on its content. After reading a passage, choose the best answer to each question. Answer all questions following a passage on the basis of what is stated or implied in the passage.According to the data answeritems
The primary purpose of the passage is to treat the potential correlation between environmental pollutants and carcinogenic effects in which of the following ways?
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答案解析：