Description : The metal, which is a constituent of vitamin B12 is - (1) Iron (2) Magnesium (3) Zinc (4) Cobalt
Last Answer : (4) Cobalt Explanation: Vitamin B12 is a "generic descriptor for compounds exhibiting the biologic activity of cyanocobalarnin: the antianemia factor of liver extract that contains cobalt, a cyano group ... lead to anemia, as well as nerve and brain damage, which may eventually become irreversible.