Final answer:
During lactic acid fermentation in muscle cells, the environment around the cells becomes more acidic due to the production of lactic acid, leading to a decrease in pH.
Step-by-step explanation:
The question addresses the effects of fermentation in muscle cells, specifically concerning the changes in the environment around the cells due to the process. The correct answer is d) The pH should decrease. This occurs because, during fermentation, particularly lactic acid fermentation, which is common in animal skeletal muscles, lactic acid is produced as a byproduct. As more lactic acid accumulates, it increases the acidity of the muscle environment, thereby lowering the pH.
It is important to note that lactic acid must be removed from the muscle via blood circulation and transported to the liver, where it can be converted back into pyruvic acid for further metabolism. The decreased pH outside the cell could potentially affect the transport of amino acids; however, whether it would increase or decrease the transport depends on several factors, including the specific transport mechanism and the buffering capacity of the environment around the cells.