Various types of tissues may be organized to form an organ
The major difference between lactic acid and alcohol fermentation is the products that are produced. In the 'L.A' fermentation, lactic acid and 150 kJ of energy is produced while in alcohol fermentation, alongside the alcohol (ethanol) and the 210 kJ of energy, carbon dioxide is produced.
In lactic acid fermentation:
C₆H₁₂O₆ ₋₋₋₋₋₋₋₋> 2C₃H₆O₃ + Δ150 kJ
while in alcohol fermentation:
C₆H₁₂O₆ -----------> 2C₂H₅OH + 2CO₂ + Δ210 kJ
I'm pretty sure it's the cell since it's the basic unit of life and can change to carry out any function