科技馆有一个磁悬浮地球仪,当它静止在如图所示位置时,地球仪竖直方向的受力分析(不计空气浮力)正确的是 ( )
人体的血液中,能够吞噬病菌、运输氧气、运输养料和废物的成分依次是( )
Steve gets on well with his classmates he has been in this class for only one month