Explanation:
Alkenes react in the cold with pure liquid bromine, or with a solution of bromine in an organic solvent like tetrachloromethane. The double bond breaks, and a bromine atom becomes attached to each carbon. The bromine loses its original red-brown color to give a colorless liquid. In the case of the reaction with ethene, 1,2-dibromoethane is formed.
The correct answer is A, Water is not used up during this process. This is because when cellular respiration occurs oxygen and glucose combine. When this takes place water is left behind when carbon is separated from glucose. Because water is being left behind it is not being used up in this process.
The third answer because there are two of each atom
