Aweightlifter is using heavy weights in short bursts for a competition. because his muscle cells are not able to take in enough oxygen to make very much atp the weightlifter begins to get fatigue in his muscles. why are his muscles feeling this way? *

1. as the cells run out of oxygen they switch to anaerobic respiration, which allows the cell to make small amounts of atp in the absence of oxygen.

2. as the cells run out of oxygen, they die off gradually and the weightlifter's muscles have fewer contracting muscle cells.

3. as the cells run out of oxygen, they begin to make ethanol (an alcohol)

4. as the cells run out of oxygen, they will continue to make the same amount of atp, since oxygen is not required to make atp.