Answer:
When one still breathes hard even after finishing the exercise is known as EPOC or extra post-exercise oxygen consumption.
Oxygen deficit refers to the condition when one cannot breathe in fast enough to get all the oxygen required by the body.
Steady-state refers to the state when the body receives the amount of oxygen required by the tissues of the body in order to generate adequate amount of energy.
In the state of oxygen deficit, the production of lactic acid takes place.
At the time of steady-state, no lactic acid gets produced or removed.
During EPOC, extra oxygen assists in getting rid of the lactic acid produced.