Which aspect of genetic makeup is most likely to alter a person's response to medication?.

Choice A rationale: While distribution can affect a person’s response to medication, it is not the aspect of genetic makeup most likely to alter this response. Choice B rationale: Absorption can affect how a drug is taken up by the body, but it is not the aspect of genetic makeup most likely to alter a person’s response to medication. Choice C rationale: Excretion, or how the body eliminates a drug, can affect drug response, but it is not the aspect of genetic makeup most likely to alter this response. Choice D rationale: Metabolism, or how the body processes a drug, is the aspect of genetic makeup most likely to alter a person’s response to medication. Genetic differences can lead to variations in drug-metabolizing enzymes, affecting how quickly or slowly drugs are metabolized.