Are all anemias caused by a lack of iron?

Vitamin and iron def. Anemia could be caused by deficiency of iron, vitamin B12 and folate (folic acid) as well as copper deficiency.
Not at all. There are 3 reasons for anemia 1- loss of blood (which contains iron} usually through the intestine in the stools. 2- bone marrow failure to make blood components. 3- hemolysis of blood i.E blood turning against red blood cells either by a drug or infection by virus, bacteria or...There are massive books on anemia. Anemia is a major component of blood disease and cancer....Thank you for asking.