单选题 The example given in the passage illustrates how ______.

A、 pure science operates independently of applied science
B、 the applied scientist discovers the basic laws of nature
C、 applied science defines all the areas in which basic research is done
D、 applied science suggests problems for the basic scientist

【正确答案】 D

【答案解析】第二段说了两类科学家之间相互关联并指出the applied scientist finds the“problem”for the theoretical scientist to work on，紧接着就列举了aircraft industry的例子，很显然是为了论证上述观点，选项D正确。