High-technology medicine is driving up the nation’s health care costs. Recent advances in cataract surgery illustrate why this is occurring. Cataracts are a major cause of blindness, especially in elderly people. Ten years ago, cataract surgery was painful and not always effective. Thanks to the new technology used in cataract surgery, the operation now restores vision dramatically and is less expensive. These two factors have caused the number of cataract operations performed to increase greatly, which has, in turn, driven up the total amount spent on cataract surgery.
Which one of the following can be inferred from the passage

单项选择题The nuclear polyhedrosis virus helps control gypsy moth populations by killing the moth’s larvae. The virus is always present in the larvae, but only every sixth or seventh year does the virus seriously decimate the number of larvae, thereby drastically setting back the gypsy moth population. Scientists believe that the virus, ordinarily latent, is triggered only when the larvae experience biological stress. If the scientists mentioned above are correct, it can be inferred that the decimation of gypsy moth larvae populations by the nuclear polyhedrosis virus would be most likely to be triggered by which of the following conditions

单项选择题Public reports by national commissions, governors’ conferences, and leadership groups have stressed the great need for better understanding of international affairs by the citizenry. If the country is to remain a leading nation in an era of international competitiveness, the need is undeniable. If there is such a need for the citizenry to have a better understanding of international affairs, then all of our new teachers must be prepared to teach their subject matter with an international orientation. If all of the statements in the passage are true, which one of the following must also be true