精选优质文档-倾情为你奉上2020届高三英语专项训练阅读理解D篇(一)A new study shows that rising levels of planet-warming gases may reduce important nutrients in food crops.Researchers studied the effects of one such gascarbon dioxideon rice. The researchers grew rice plants in a controlled environment. They set carbon dioxide levels to what scientists are predicting for our planet by the end of the century. They found that the resulting rice crops had lower than normal levels of vitamins, minerals and protein.