Individuals who are heterozygous for the sickle-cell allele suffer less from the attack of malaria because a small percentage of the red blood cells are sickle-shaped. They are more resistant to malaria than individuals who have two copies of the normal haemoglobin allele. Heterozygous individuals have a better chance of surviving and reproducing in regions where malaria is prevalent since they do not fully contract the disease.
I believe it is Wegener's theory did not explain how the continents could move.
lots of waste and dead leaves and things like that
dont plagarise ;)
