▶ Your Answer : In the reading passage, the author gives several points to maintain that it is inevitable to hinder the intrusion of the zebra mussel into North America and it has several negative impacts on new environment. The professor in the lecture contradicts the author's claim by stating that the migration of the mussel can be controlled. First, the professor contends that the methods that the mussels are cling to the bottom of the ship is no longer feasible since the human being enriched their know-how to deal with this problem. The ships are able to empty its bottom by restoring oceanic water to kill the mussels. This counters the reading passage's claim that the trespass is untouchable because the mussels are viable within the newly devised water route between Europe and North America. Next, the professor suggests that the mussels were liberated from the predators only in the beginning phase of their migration. The birds turn their feeding habit into consuming the mussels, wiping them out before they were prevalent in the new area. This casts doubt on the reading passage's argument that the new residence were vanquished by the mussels attributable to adaptation to diverse surroundings, fast rate of procreation, and having no predators. Finally, the professor argues that even though the mussels are enough to take supremacy in the new environment, it will not diminish the number of other species. They are able to generate a range of ingredient for other fishes, such as bottom feeding species, to ingest them, activating positive effect on the ecosystem. This refutes the reading passage's suggestion that it has acted negatively on the other species by exhausting the main food source, the plankton.
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