what substance in least cells are responsible for Breaking Down sugar into carbon dioxide and ethyl alcohol

The spelling mistake is present in the question, so the right question is as follows:

what substance in yeast cells are responsible for Breaking Down sugar into carbon dioxide and ethyl alcohol?

Zymase

Explanation:

Zymase is an enzyme that is responsible for breaking down sugar into carbon dioxide and ethyl alcohol in a yeast cell.

The whole process of formation of ethyl alcohol in the presence of yeast enzyme zymase is called fermentation. The process fermentation must occur in the absence of air because the zymase enzyme unable to perform its function in the presence of air.

Hence, the correct answer is "Zymase enzyme".