Answer:
increases resistance to malaria
Explanation:
Sickle cell anemia is a genetic disorder in which the shape of red blood cells changes from oval to that of sickle. Because of this change in shape, the red blood cells tend to get stuck in the blood vessels and block them. Apart from this, the life span of sickle shaped red blood cells shortens leading to anemia. But, having sickle cells is advantageous too. Those people who have this disease can never acquire malaria. The parasite known as plasmodium which causes malaria can not infect sickle shaped hemoglobin that is why people having this disease are resistant against malarial infection.
