单项选择题
A.38mg/d B.48mg/d C.58mg/d D.68mg/d E.78mg/d
A.11.5mg/d B.13.5mg/d C.15.5mg/d D.16.5mg/d E.21.5mg/d
A.钼 B.硒 C.铜 D.锰 E.铬