A:C,H,N,P,Mg
B:Cl,Fe,S,N,Mg
C:B,Cu,Zn,Mn,Mo
D:N,P,K,Cu,Fe,I
“羌笛何须怨杨柳,春风不度玉门关”描述的是( )
胶体区别于其它分散系的本质特征是( )