Answer:
The correct answer will be- red blood cells (RBC)
Explanation:
Malaria has proved endemic to the human species as it has killed the humans in large numbers and it has acted as one of the strongest selective force.
The malaria disease has caused the mutation in the genes in the red blood cells which carries the oxygen to different organs of the body. The mutation in the genes causes the circular shape of red blood cell to sickle-shaped cells which carry less oxygen to the organs.
The change in the shape of red blood cell provides resistance against malaria disease but it becomes a problem where malaria is not a problem.
Thus, red blood cells (RBC) is the correct answer.