A．Because scientists insist they are harmless. B．Because the protestors aren't very big and powerful. C．Because they are critical for understanding and curing human diseases. D．Because there are enough regulations to protect animals from abuse.
A.Because B. B．Because C. C．Because D. D．Because
【参考答案】
C 解析：题干询问为什么科学家认为动物的实验还必须继续，文章中的关键句为：They can't do witho......