Question

TPO 21 听力Lecture第3篇 第5题Why does the professor mention the brown tree snake?为什么答案是A?

Why does the professor mention the brown tree snake?A. To support a hypothesis about the evolution of constrictor snakes.B. To support a hypothesis that venomous snakes evolved from constrictor snakes.C. To give an example of a snake species that was never venomous.D. To give an example of a type of snake that can change its color.

Answer 1

Professor: Constrictors have evolved to kill their prey by crushing, but perhaps they once were venomous, and then at some point their venom-producing apparatus wasn’t needed anymore, so it gradually disappeared. There’s one species of snake, the brown tree snake that uses both constriction and venom, depending on its prey. So, well, it is possible.
教授讲述了蟒蛇进化的一种可能：蟒蛇进化出了挤压杀死猎物的技能，它们可能曾经是有毒蛇，但在某一时间，产生毒液的器官不再有用，这个器官就慢慢消失了。接着教授举例the brown tree snake（褐色树蛇），所以举这个例子是为了支撑蟒蛇进化的假设，A 选项正确。