《中国居民平衡膳食宝塔》中，所占比重最少的食物是（）

A.谷类食物

B.蔬菜和水果

C.肉类等动物性食物

D.奶类和豆类

E.油脂类

The variation for most given areas undergoes（）change，the amount of which is also noted on charts.

A.an annual

B.a constant

C.a variable

D.an unstable