An association football (soccer) match is presided over by a referee, whom the Laws of the Game give full authority to enforce the Laws of the Game in connection with the match to which he has been appointed (Law 5). The referee is oftentimes assisted by two assistant referees, and sometimes by a fourth official.
Barfoed's test. Barfoed's test is a chemical test used for detecting the presence of monosaccharides. It is based on the reduction of copper(II) acetate to copper(I) oxide (Cu2O), which forms a brick-red precipitate.
Blood alcohol content, or BAC, is one of the most commonly used ways of determining not only if a person has been drinking alcohol, but also how much alcohol a person has consumed. Although a Breathalyzer test can estimate a person's BAC, to determine actual blood alcohol content, a blood sample must be used. blood sample for alcohol content is taken in the same way as any other blood sample, using a needle. The needle is placed into a vein and a collection tube is inserted into the back of the needle. The needle is withdrawn, and the collection tube is sent to a lab for testing.