It's something to do with the fact that having sickle cell anaemia reduces the chances of contracting malaria, obviously a very common disease in Africa. I'm not quite sure what the link is but hopefully this helps a little bit?
Your answer is hypothesis i think. There were no given answer choices so i went with what i think youre asking.
I n the F1 generation, there will be no recessive offspring but in the F2 generation there is a 25% of offspring being recessive.
You can find more info about percentages by observing images. called Punnett Squares.
Hope it helped,
BioTeacher101
Transporting substances in a cell. proteins are transported either in or out of the cell.