Explanation:

Vitamin B_12 (Cyanocobalamin) is a water soluble vitamin. It contains a metallic ion cobalt.Vitamin B12 is a nutrient that helps keep the body's nerve and blood cells healthy and helps make DNA, the genetic material in all cells. Vitamin B12 also helps prevent a type of anemia called megaloblastic anemia that makes people tired and weak. Weakness and fatigue are common symptoms of vitamin B12 deficiency. They occur because your body doesn't have enough vitamin B12 to make red blood cells, which transport oxygen throughout your body. As a result, you are unable to efficiently transport oxygen to your body's cells, making you feel tired and weak.