2020托福听力练习：鸡心螺毒液使鱼类昏迷（下载）

　　It may not be the legendary matchup squid vs octopus, but imagine this fight:

　　sea-dwelling cone snail versus tiny fish!

　　Who wins? Well, true, the fish can dart away.

　　But the snail has chemical weapons.

　　"So they use a whole cocktail of compounds and most of them are neurotoxins and they just completely wipe out the prey's physiology, right, so they prey cannot respond anymore."

　　Helena Safavi, a biologist at the University of Utah.

　　She and her colleagues discovered that the cone snail's venom contains not only neurotoxins, but insulin, too—which the snail's prey take in through their gills.

　　And that insulin overdose causes the fish's blood sugar to plummet, depriving its brain of energy, and inducing a coma.

　　"And that's what happens when you give people an insulin overdose—you can cause coma and then death depending on the amount of insulin."

　　They report the findings in the journal Proceedings of the National Academy of Sciences.

　　If this all sounds like something out of a murder mystery…well, it is.

　　The paper actually cites the Claus von Bulow trials in the 1980s.

　　Von Bülow was ultimately found not guilty.

　　But in this evolutionary struggle between snail and fish…it's now clear who done it.And how.