Answer:A deficiency of vitamin B12 can cause FOLATE DEFICIENCY ANAEMIA.
Folate or iron is an element necessary for haemoglobin production,the pigment present in RBC(Red Blood Cell). The deficiency of iron results in a decreased production of haemoglobin hence less RBCs in blood. This condition eventually results in ANAEMIA where the RBC per mm of blood is below normal, causing severe health risks.