What condition is defined as having too few red blood cells, resulting in reduced oxygen-carrying capacity?

Anemia is characterized by a decrease in the number of red blood cells or a deficiency in hemoglobin, leading to a reduced capacity to transport oxygen throughout the body. This condition can result from various factors, including iron deficiency, chronic diseases, or genetic disorders. Symptoms often include fatigue, weakness, and pallor, as the body struggles to deliver sufficient oxygen to tissues and organs.

In contrast, leukemia is a type of cancer that affects blood cells, primarily resulting in an overproduction of abnormal white blood cells. Thrombocytopenia refers to a low platelet count, which affects blood clotting rather than oxygen transport. Hemophilia is a genetic disorder that impairs the blood's ability to clot, which is unrelated to the number of red blood cells. Each of these conditions has distinct implications for the body's function and health, making anemia the correct choice in this context.