【单选题】

Geographers say that what defines a place are four properties: soil, climate, altitude,　　　 and aspect, or attitude to the Sun. Florida’’s ancient scrub demonstrates this principle. Its 　　　 soil is pure silica, so barren it supports only lichens as ground cover.(It does, however, 　　　 sustain a sand-swimming lizard that cannot live where there is moisture or plant matter (5)　 the soil.) Its climate, despite more than 50 inches of annual rainfall, is blistering desert 　　　 plant life it can sustain is only the xerophytic, the quintessentially dry. Its altitude is a 　　　 mere couple of hundred feet, but it is high ground on a peninsula elsewhere close to sea 　　　 level, and its drainage is so critical that a difference of inches in elevation can bring major 　　　 changes in its plant communities. Its aspect is flat, direct, brutal―and subtropical. (10)　 Florida’’s surrounding lushness cannot impinge on its ’’desert scrubbiness.　　　 This does not sound like an attractive place. It does not look much like one either; 　　　 Shrubby little oaks, clumps of scraggly bushes, prickly pear, thorns, and tangles. "It appear 　　　 Said one early naturalist," to desire to display the result of the misery through which it has 　　　 Passed and is passing."By our narrow standards, scrub is not beautiful; neither does it meet (15)our selfish utilitarian needs.Even the name is an epithet, a synonym for the stunted, the 　　　 scruffy, the insignificant, what is beautiful about such a place 　　　 The most important remaining patches of scrub lie along the Lake Wales Ridge, a chain 　　　 of paleoislands running for a hundred miles down the center of Florida, in most places less 　　　 than ten miles wide. R is relict seashore, tossed up millions of years ago when ocean levels (20)　 were higher and the rest of the peninsula was submergeD、That ancient emergence is 　　　 precisely what makes Lake Wales Ridge so precious: it has remained unsubmerged , its 　　　 ecosystems essentially undisturbed, since the Miocene er

A、As a result, it has gathered to 　　　 itself one of the largest collections of rare organisms in the worlD、Only about 75 plant 　　　 species survive there, but at least 30 Of these are found nowhere else onEarth. According to the passage, why is the Lake Wales Ridge valuable
A、It was originally submerged in the ocean.
B．It is less than ten miles wide.
C．It is located near the seashore.
D．It has ecosystems that have long remained unchanged