Incomparison,mortalityofthecrustacean,Gammaruspulex,firstoccurredatconcentrationsinthemgl-1range,andthenonlyaftercontinuousexposureforseveraldays.
Generate a sentence using the above characters:
In comparison, mortality of the crustacean, Gammarus pulex, first occurred at concentrations in the mg l-1 range, and then only after continuous exposure for several days.