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?
Cell wall: strong; supporting layer around the cell membrane in plant cells
i pretty sure its Cytokinesis and Spindle Fibers.
Organisms that use the same resources because there may not be enough for all, so it then becomes a competition of who gets it and who doesn't.
