问题详情

What conclusion can be drawn from the scientists observation？

A．Insects have developed some sort of resistance to man-made poisons.

B．Insects have been eating plants for about 250 million years.

C．Farmers sometimes use a combination of two or three insecticides at once.

D．New insects mate with insects which survived from a certain kind of insecticide.

请帮忙给出正确答案和分析，谢谢！