試題詳解

67. You enjoy learning about history by traveling throughout North America studying gravestones. You notice that gravestones from 1900 and earlier usually host many types of lichens. But in one cemetery, lichens are entirely absent, even from old gravestones. Given what is known about lichens, the cemetery without lichens probably ______.
(A) has an unusually dry climate
(B) is subject to extremely cold winter temperatures
(C) gets a great deal of rain, which favors the growth of competing bacteria
(D) has a high population of fungi that parasitize lichens
(E) is close to a source of air pollution