The process by which alcohol is removed from the bloodstream involves mainly:

Metabolism and some excretion is the main process by which alcohol is removed from the bloodstream. This is because when we drink alcohol, our body breaks it down into smaller molecules through metabolism, which then allows for some of it to be excreted through bodily fluids such as sweat, urine, and breath. Option A, excretion, is not the main process as it only accounts for a small portion of alcohol removal. Option B, digestion, is incorrect because alcohol does not undergo significant digestion in the stomach or intestines. Option D, absorption, is also not the main process as alcohol must first be absorbed into the bloodstream before it can be metabolized and excreted. Therefore, option C, metabolism and some excretion, is the most accurate and complete answer.