A.異食癖 B.皮膚不全角質(zhì)化 C.腳蹄爪毛生長(zhǎng)緩慢 D.觀星姿勢(shì)
A.鐵 B.鎂 C.硒 D.鋅
A.0.25%~0.5% B.0.1% C.1%~2% D.3%~5%