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C. Median toxicity.
Explanation – The frequency of drugs are given based on its toxicity or the side effects in the body. All drugs have certain half-life in which there action is maximum and after that the drug is removed through the urine primarily.
Different people react differently to a drug and hence the doctors prescribe the anti-tablets for the side effects occurring. The drug for cold is prescribed after four hours because its effect gets reduced and has to be removed from the body.
Answer: The human circulatory system has a complex network of blood vessels that reach all parts of the body. This extensive network supplies the cells, tissues, and organs with oxygen and nutrients, and removes carbon dioxide and waste compounds.
Explanation: