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(单选题)( ) (单选题)( ) (单选题)( ) (单选题)( ) (单选题)( ) (单选题)( ) (单选题)( ) (单选题)What does “such altruism” (in bold) in the last paragraph re (单选题)What can we infer from Dr. Cohn’s team’s study? ( ) (单选题)Which of the following sentences can best fit in the blank i