End product of anaerobic respiration is :

CONCEPT: Cellular respiration breaks down glucose to release energy. When oxygen is unavailable, cells respire anaerobically (fermentation) instead of completing the full aerobic breakdown into carbon dioxide and water. Two common fermentation routes exist: yeast and many plant cells convert glucose into ethyl alcohol (ethanol) and carbon dioxide — this is alcoholic fermentation — while animal muscle cells convert glucose into lactic acid under oxygen debt.

APPLICATION: Since the question does not name a specific organism, and lactic acid (the animal-muscle fermentation product) is not among the given choices, the intended reading is the yeast/plant alcoholic-fermentation pathway. In that pathway, glucose is broken down anaerobically to release ethyl alcohol together with carbon dioxide — the compound formed at the end of this pathway.

CROSS-CHECK:

• Glucose itself is the starting substrate fed into the pathway, consumed before fermentation runs, not released at its end.

• Malic acid arises from aerobic Krebs-cycle activity in plant-cell metabolism, a separate route from anaerobic glucose fermentation.

• Because alcoholic fermentation is one of the anaerobic pathways available to organisms such as yeast, a matching product exists among the listed choices.