进入组织或无菌器官内部的器械,或与破损的组织皮肤黏膜密切接触的器材和用品的危险性分类是()。
A.高度危险性物品
B.中度危险性物品
C.低度危险性物品
D.无危险性物品
参考答案:A
When shall the stand-on vessel change course and speed?()
A.the stand-on vessel may change course and speed at any time as it has the right of way
B.after the give-way vessel sounds one blast in a crossing situation
C.when action by the give-way vessel alone cannot prevent collision
D.when the two vessels become less than half a mile apart
下列关于诱变育种的说法,正确的是()
A.用一定剂量的射线处理萌发的小麦种子,可以使其发生基因突变形成新的物种
B.用一定剂量的射线处理萌发的水稻种子,可以定向产生具有优良性状的水稻新品种
C.诱变育种可以提高基因突变频率,从中选育出符合人类需求的新性状[
D.诱变育种的原理就是人工诱导生物发生基因突变