单项选择题
A.铁 B.锌 C.碘 D.硒
A.0.1~0.5 B.0.5~0.8 C.1.0~1.5 D.1.2~1.8
A.铁 B.锰 C.铜 D.锌
A.1% B.15%~40% C.1%~5% D.0.5%~10%
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