問題詳情
38. Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element thatis needed by all forms of life?
(A) calcium
(B) iron
(C) iodine
(D) sodium
(E) potassium
參考答案
答案：B
難度：困難0.285714
統計：A(1),B(2),C(1),D(0),E(1)