韧皮部运输 phloem transport
参考答案：
叶片中形成的同化物以及再利用的矿质养分通过韧皮部筛管运移到植物其他部位的过程。
标出如图中所示地磁场的磁感线方向．
A PM wanted to show management, visually, how quality controls were affecting processes. The best tool to accomplish this is （）.
A.Diagrams
B.Histograms
C.Flowcharts
D.Controlcharts
