Which of the Following Statements Are True of Trace Elements

Which of the following statements are true of trace elements (Select all that apply) ?

A) Iron is part of the hemoglobin in RBCs.
B) Vitamin B12 contains the mineral copper.
C) The transmission of nerve impulses depends on sodium and potassium.
D) Cobalt is needed for the hormone thyroxine.
E) Phosphorus is part of DNA and RNA.
F) The mineral necessary for blood clotting is iodine.
G) The mineral that helps store oxygen in muscle cells is magnesium.
H) Sulfur is part of some proteins.