左心室的流出道是()
A.动脉圆锥
B.主动脉前庭
C.腔静脉窦
D.左房室口
E.右房室口
参考答案:B
下列具有输导组织的是( )
A.水绵
B.墙藓
C.海带
D.肾蕨
()is a high layer of cloud in the front of small flakes or cauhflower,white in colour with no dark shadows in between.
A.Cirrostratus
B.Cirrus
C.Cirrocumulus
D.Altostratus