What condition is characterized by a decrease in red blood cells and hemoglobin?

The condition characterized by a decrease in red blood cells and hemoglobin is anemia. Anemia is a medical term that refers to a drop in the number of red blood cells or the amount of hemoglobin they contain, which is essential for transporting oxygen throughout the body. This decreased ability to carry oxygen leads to symptoms such as fatigue, weakness, and pallor, among others.

In contrast, hyperemia refers to an increased blood flow to tissues, often resulting in redness and warmth, but it does not involve a decrease in red blood cells or hemoglobin. Leukopenia, on the other hand, is a deficiency of white blood cells and is unrelated to red blood cells or hemoglobin levels. Polycythemia signifies an increase in red blood cells, which is the opposite of the condition described. Thus, anemia is the correct answer because it specifically denotes a reduction in both red blood cells and hemoglobin.