Anemia (6 letters) is a medical condition characterized by a deficiency of red blood cells, which are responsible for carrying oxygen throughout the body. ANAEMIA (7 letters) is a variation of ANEMIA, and is caused by a lack of iron in the diet. MARROW (6 letters) is the soft tissue found in the center of bones, and is responsible for producing red and white blood cells. SERUM (5 letters) is a clear liquid component of blood, and is used to treat ANEMIA by providing essential vitamins and minerals.