Question

sickle cell anaemia shows. oftain epistrasis.co-dominance.pleiotropy.incomplete dominance

Answer 1

I think it shows codominance.

Answer 2

Pleiotropy is a phenomenon on which one gene affects multiple characteristics or a condition in which one gene code for the expression of several different and unrelated traits.

For example: Sickle cell anemia. It occurs due to a mutation in the HBB gene.  

It is a pleiotropic disease because a change in one nucleotide produces an expression which produces consequences throughout the body.