Which is produced by alcoholic fermentation?
I. ethanol
II. lactic acid
III. carbon dioxide
IV. oxygen
3 answers
https://www.google.com/search?source=hp&ei=yjHFW8XvOIbazgLAy5XQBg&q=produced+by+alcoholic+fermentation&btnK=Google+Search&oq=produced+by+alcoholic+fermentation&gs_l=psy-ab.3..0i22i30l8.5042.5042..6066...0.0..0.283.472.0j1j1......0....1j2..gws-wiz.....0.yPD261RCyo4
There are two correct products listed, I am not certain if your teacher meant that, but those bubbles are a product.
I suspect the teacher missed that point.