Final answer:
Sickle cell anemia is a genetic disorder with sickle-shaped red blood cells, more common in individuals of African descent, making the correct answer (a) Blacks.
Step-by-step explanation:
Sickle cell anemia is a genetic disorder that leads to the production of abnormally shaped red blood cells that are crescent or sickle-shaped instead of round. This abnormal shape is due to a mutation in the hemoglobin gene, causing hemoglobin S. The sickle-shaped cells can obstruct blood flow in capillaries, leading to severe health complications. Sickle cell anemia is particularly prevalent among individuals of African descent, and to answer the student's question, sickle cell anemia is most commonly seen in blacks.