【简答题】Plastic and traces of hazardous chemicals have been found in Antarctica, one of the world’s last great wildernesses, according to a new study. Researchers spent three months taking water and snow samp...
【单选题】To label their produce as organic, farmers have to obtain a certificate showing that no ________ chemicals have been used to kill pests on the farm for two years.
【单选题】To lable their product as organic ,famers have to obtain a certificate showing that no ______chemicals have been used to kill pests on the farm for two years.