TOEFL Reading: ETS-TOEFL阅读机经 - 3JB799C473R4X8JQL$

According to paragraph 1, which of the following presents a serious difficulty for the predators that hunt animals grazing in grasslands? A. It is difficult to find grazers in grasslands when they are feeding with their heads down. B. Predators lack places to hide from prey in grasslands. C. It is difficult for predators to outrun grazers on grasslands. D. Grazers in open grasslands tend to be very large animals.