The changes in the grape juice happened due to the alcoholic fermentation of the grape juice that occurs due to the presence of aerobic bacteria. The presence of yeast is the main reason behind the process of fermentation taking place. The froth is produced due to the presence of the formation of acid and carbon dioxide.
I don't think the answer is A as that seems a bit drastic, I think it's C.
It would not be a sex cell. a sex cell definition it has half the chromosomes. Hope this helps.
