In this set of materials, the reading brings three reasons for spread of Zebra mussel, which is native to Eastern Europe, in parts of Eastern North America. However, the speaker in the lecture is in disagreement with whatever the author mentions. According to the professor the population of Zebra mussel could be controlled. First, the writer believes that the invasion of the Zebra mussel might not be stoppable. On the other hand, the lecturer claims that such a theory is not true. He explains that the dominant way that Zebra mussel could travel is using ballast water which get into the coast of northern America at last. The point is the salt of the water ocean will kill the Zebra mussel. Second, the author states that the Zebra mussel
