Question 9

The results of two new experiments suggest that rats are surprisingly selfless.

This sentence would best fit after sentence 8, as it serves to summarize and reflect on the findings presented in the preceding sentences about the altruistic behaviors of rats observed in experiments.

A) After sentence 1

Placing the sentence after sentence 1 would disrupt the flow of the passage. Sentence 1 introduces the concept of positive perceptions of rats, while the suggested sentence focuses on experimental findings regarding selflessness, making this placement contextually inappropriate.

B) After sentence 3

Inserting the sentence after sentence 3 would be illogical since sentence 3 describes the setup of the first experiment. The results regarding altruism are not yet revealed, and thus, mentioning selflessness at this point would be premature and out of context.

C) After sentence 8

This is the most suitable placement for the sentence, as it comes after the presentation of the experimental results demonstrating altruistic behavior in rats. It effectively summarizes the findings and emphasizes the surprising nature of these behaviors, making it a fitting conclusion to the discussion of the experiments.

D) After sentence 11

Positioning the sentence after sentence 11 would be ineffective, as this sentence discusses the ongoing debate among scientists regarding the interpretations of the experiment results. Introducing the idea of selflessness here would not align with the skeptical tone and context of the surrounding sentences.

Conclusion

The sentence about the selflessness of rats is best placed after sentence 8, as it encapsulates the essence of the findings from the experiments discussed earlier. The other options do not provide a logical or contextual fit, either interrupting the flow or contradicting the surrounding content. Thus, option C is the definitive choice for effectively summarizing the altruistic nature of rats demonstrated in the experiments.