The insecticide DDT was introduced in the 1950s, and the rates of malaria dropped significantly. DDT was later found to be toxic to birds and other animals, and it was discontinued in 1964. As a result, rates of malaria began to rise. How can the effects of DDT on society be characterized?

DDT had a positive effect because its use significantly reduced malaria rates. It also had a negative effect because it was toxic to birds and other animals, leading to its discontinuation. Therefore, its effects on society were both positive and negative, choice C.

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