Final answer:
The oxygen needed for the liver to convert lactic acid back to glucose after exercise is known as the oxygen debt, which is part of the Cori Cycle.
Step-by-step explanation:
The amount of oxygen needed to support the conversion of lactic acid to glucose by the liver is called the oxygen debt. During exercise, when oxygen supply is insufficient for the energy needs of muscles, glucose is broken down into lactic acid through a process called glycolysis.
This lactic acid can accumulate and contribute to muscle fatigue. To convert this lactic acid back to glucose, which the body can use again for energy, oxygen is required. This process, largely occurring in the liver, is part of the Cori Cycle, which helps to manage energy resources during and after physical exertion. The oxygen debt is essentially the extra oxygen intake needed after exercise has ceased in order to restore the body to its pre-exercise state.