Respuesta :
Answer:
The correct answer is "lactic fermentation".
Explanation:
Lactic fermentation is a type of anaerobic respiration that occurs in muscle cells as a way to produce energy when not enough oxygen reach the cells. This happens when a person is performing anaerobic exercise for a considerable period of time or without proper training, like Bradley that tried to run a marathon without any training. Lactic fermentation produces lactic acid build up on muscles, which is what is causing the cramps on Bradley's legs.