Critical Reasoning

European green crabs are an invasive species which have recently colonized the Northwest coast of North America, among other places. They disrupt ecosystems and prey heavily on native shellfish. However, in Europe, the population of green crabs is kept relatively low by a parasitic barnacle called Sacculina carcini. This barnacle is hardy and could likely be introduced to areas where the European green crab threatens to ruin established ecosystems.

Which of the following, if true, most strongly supports the argument that it would NOT be advisable to attempt to eliminate European green crabs from the Northwest coast of North America by introducing to the area the parasitic barnacle discussed above?


(A) In their native habitat, the parasites often threaten the elimination of local green crab populations.

(B) European green crabs are also occasionally preyed upon by fishes, gulls and other species of crab in their native ecosystems.

(C) Though the parasite may survive in North American waters, no large-scale facility for breeding and harvesting the parasites exists as of yet.

(D) Many other invasive species on the Northwest coast of North America are not suitable hosts for this parasite.

(E) Though the barnacle cannot reproduce inside of native shore crabs, it can still infect and kill native shore crabs