题目选项分析

Professor: A marine biologist argues that transmission of sea lice from farm salmon to wild salmon is unlikely in the Broughton Archipelago, British Columbia, citing numerous studies suggesting that salinities less than 30 parts per thousand are unfavorable to sea-lice survival. The biologist concludes that the archipelago's 25-30 parts per thousand salinity range between March and June, the critical period for wild salmon migration, tends to suppress sea-lice proliferation. But a review of the literature shows that salinities of 25-30 parts per thousand in combination with British Columbia's cool spring temperatures favor the flourishing of sea lice. In this passage, the professor attempts to undermine the biologist's argument by

【选项】pointing out that a condition claimed to be necessary for sea-lice survival is not sufficient for it