TOEFL Reading: ETS-TOEFL阅读机经 - AD1C1CE3633K88O3L$

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. Dead and dry grasses that form on the soil surface in grasslands are called mulch. B. In summer, people use dry grasses and their dead remains to fuel fires in grasslands. C. In grasslands, summer fires started either by lightning or by people are fueled by dry grasses and their dead remains at the soil surface. D. It is always easy to find fuel to use for fires in grasslands because dry grasses and mulch accumulate at the soil surface during summers