When cell a recognizes cell b in the body, what is cell a actually recognizing?

Find and describe the climate zone in which you live,where else in the world do you find this climate zone? do you have any ideas about why the climates might be similar?

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

Which system revise and send electrical signals throughout the body