Breathing hard during exercise brings oxygen to your muscles, which what process release energy to fuel your workout

This statement is a fact: "Breathing hard during exercise brings oxygen to your muscles, which helps what process release energy to fuel your workout."
This is because
>During exercise, your muscles have to work harder. Working harder increases their demand for oxygen, which is why your breathing and heart rates increase, to pull more oxygen into the bloodstream.
> The oxygen that reaches your muscles never leaves as you exercise, but rather sets to work immediately converting the available glucose into ATP.