I’m pretty sure its the second one.
Because;
- turning glucose into atp is the whole point of cellular respiration. Therefore, it must be the input into the equation, so the 4th choice is out.
- lactose has nothing to do with cellular respiration, so the 1st choice is out.
- ethyl alcohol is a product of alcoholic fermentation, not an input. For this reason, the 3rd choice is out.
- the answer should then be the 2nd choice
Hope this helps :)
