Answer: natural selection
Answer:
here.
Explanation:
Due to the prevalence of malaria in Africa, the allele for sickle cell anemia (HbS) provides a selective advantage. That's why it remains in the population.
A normal African person (HbAHbA), with normal haemoglobin, will not die of anemia, but will die of malaria.
An African person with sickle cell anemia (HbSHbS), with abnormal haemoglobin, will die of anemia.
A heterozygous African person (HbAHbS), with half of his red blood cells (RBCs) being normal and the other half being sickle-shaped, will neither die from anemia, nor malaria since the plasmodium will be incapable of completing its life cycle in the abnormal RBCs.
Thus heterozygous African people will grow, reproduce and pass on the HbS allele to the next generations.
Some facts about Water erosion :
Water erosion is the detachment and removal of soil material by water. The process may be natural or accelerated by human activity. ... Water erosion wears away the earth's surface. Sheet erosion is the more-or-less uniform removal of soil from the surface.
Water and Wind Erosion (cause)
Water erosion is the removal of soil by water and transportation of the eroded materials away from the point of removal. Water action due to rain erodes the soil and causes activities like gully, rill, and stream erosion leading to the downstream effects of flooding and sedimentation.
If the doctor recommends dialysis
for someone who has kidney disease and he goes for a home-treatment option, he most
likely chose hemodialysis. Home hemodialysis (HHD) is the option that offers
freedom to be treated outside of the dialysis center.