How is the structure of a nerve cell different from that of a red blood cell? Why do cells differ in shape and size? PLZ HELP

Blood cells are a lot smaller than nerve cells and have a disc-shaped structure, both great traits for moving quickly through small spaces. Their disc shape also provides them with a big surface where lots of oxygen can enter the cell.

hope it helps

Normal genotype: AA
sickle-cell genotype: aa   ( It's a recessive trait)
heterozygote's genotype: Aa

In  the Hardy-Weinberg Equilibrium equation, the recessive allele is represented by q².
The proportion of the allele for the sickle cell is 0.10, so we only need to do the square rote to determine the frequency of the allele: √0.10
0,32