In which kinf of solution is the concentration of solutes the same inside and outside of the cell?

In familial hypercholesterolemia individuals homozygous for the allele causing the disorder completely lack receptors on liver cells that take up cholesterol from the blood stream. heterozygous have one-half the number of receptors while individuals homozygous for the normal allele are phenotypically normal. this is an example of a.epistasis b.complete dominance c. incomplete dominance d. codominance

The following hormone had their receptors in the cell membrane except a-insulin b-tsh c-gh d- cortisol

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?