第19题: [单项选择]People in a large area any possess the same DNA thread because______. A. DNA is characteristic of a region B. they are beyond doubt of common ancestry C. DNA strand has the ability to identify individuals D. their unique identification can be provided via DNA 参考答案:B 答案解析:细节题。题干是第一句中there are also regions of the DNA strand..(也有一些区域具有同样的DNA线索)的同义转述,原因就是because it is inher
第32题: [单项选择]对抛射剂的要求不包括() A. 常温下的蒸气压大于大气压 B. 无色、无味、无臭 C. 无毒、无致敏反应和刺激性 D. 性情温和,常温下不与药物发生反应 E. 不易燃、不易爆 参考答案:D 答案解析:对抛射剂的要求是:①常温下的蒸气压大于大气压;②惰性,不与药物等发生反应;③无色、无味、无臭;④不易燃,不易爆炸;⑤无毒,无致敏反应和刺激性。所以答案为D。