What condition arises due to a lack of sufficient red blood cells or hemoglobin?

Anemia is a condition that specifically arises from a deficiency in the number of red blood cells or insufficient hemoglobin in those cells. Hemoglobin is the protein within red blood cells responsible for transporting oxygen from the lungs to the rest of the body. When either the quantity of red blood cells is low or the hemoglobin content is diminished, the body's tissues and organs may not receive adequate oxygen to function properly, leading to symptoms such as fatigue, weakness, and pallor.

Leukemia, while it involves abnormal white blood cells, is not characterized by a lack of red blood cells or hemoglobin. Thrombosis refers to the formation of a blood clot within a blood vessel, which is a different pathological process, and embolism is related to a clot or other substance traveling to obstruct a blood vessel elsewhere. Neither of these conditions pertains to the deficiency of red blood cells or hemoglobin, which is the hallmark of anemia.