单选题 The species of fauna and flora remaining in Tibet after the Pleistocene glaciation can properly be called continental because they ______.

A、 are originally found in continental climates
B、 are the only life forms in Tibet, which is as big as a continent
C、 have been found in other parts of the Asian continent
D、 are found in land mass that used to be a separate continent

【正确答案】 A

【答案解析】从第三段中“Thus after the end of the glaciation there were only a few varieties of life extant from the original continental species．”一句可知A是正确答案。