Vaccines are used to prevent illness. most vaccines are given as injections or shots. before a doctor gives a patient a shot, the doctor wipes the skin with rubbing alcohol. what is the main reason for wiping off the skin?

If there is bacteria on your skin, inserting a syringe into it may cause the bacteria to enter your body and into your bloodstream (can lead to blood poisoning). By using rubbing alcohol on your skin before getting a vaccination, the bacteria dies, and you're skin gets disinfected. 

Biomagnification process occurs when certain toxic chemicals and pollutants such as heavy metals, pesticides or polychlorinated biphenyls (PCBs) compounds go up the food chain by working their way through the environment and into the soil or the water systems after which they are eaten by aquatic animals or plants,

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