Answer:
The best answer to the question: Anemia can be caused by a diet lacking in which nutritional substances?, would be, D: Folic acid and vitamin B12.
Explanation:
Anemia, is usually defined as a problem in the formation of red blood cells, or, erythrocites. Usually, there are a number of nutrients, such as vitamins and minerals, that play a vital role in the formation of these erythrocites. One such mineral is iron, which is why, when it is lacking in the diet, it can cause an anemia called iron-deficiency anemia. In this case, the anemia, which is either a reduced production of red-blood cells, or, cells that are incapable of carrying out their duty as oxygen-transporters, is caused by a dietary deficiency. Another form of this can be when the body itself, through an illness, is incapable of producing these cells. However, aside from iron, there are other two nutrients that are vital in the correct formation of erythrocites, and in their being efficent transporters: folic acid, also known as folate, and vitamin B12, both necessarily supplied by the diet, as the body cannot produce them.