单项选择题
单项选择题 Geographers and historians have traditionally held the view that Antarctica was first sighted around 1820, but some sixteenth-century European maps show a body that resembles the polar landmass, even though explorers of the period never saw it. Some scholars, therefore, argue that the continent must have been discovered and mapped by the ancients, whose maps are known to have served as models for the European cartographers. Which of the following, if true, is most damaging to the inference drawn by the scholars
单项选择题 Bracken, a poisonous weed, is spreading and damaging much pastureland in the Northern Hemisphere. One potentially inexpensive and self-sustaining countermeasure is to introduce natural enemies of the plant; therefore, some scientists have proposed to control bracken by a release of brackeneating moths native to the Southern Hemisphere into brackeninfested areas in the Northern Hemisphere. If the scientists’ proposal for controlling bracken is adopted, which of the following is a necessary condition for its success
单项选择题 REVENUE FOR STORE X DURING WEEK 1 During week 1, revenue from eggs provided what percent of the total revenue for store X