I'd be happy to help with that question!
In lactic acid fermentation, which occurs in muscle cells, the process is triggered when oxygen is in low supply. When the muscles are working hard and the demand for energy is high, the oxygen supply may not meet the demand. In such cases, the cells switch to lactic acid fermentation as a way to produce energy without the need for oxygen.
During this process, glucose is broken down into lactic acid, which helps in providing the necessary energy to the muscle cells. This mechanism is essential to continue muscle function when oxygen availability is limited during intense physical activity or when the body is under stress.
So, in answer to the question, option A: oxygen is in low supply, is the correct choice for when lactic acid fermentation occurs in muscle cells.
Let me know if you need further clarification or have any more questions!
