After several miles of running and sprinting in intervals, the runner’s muscles ache and feel fatigued. which is the best explanation for what has occurred?
the runner's muscles have accumulated lactic acid.
the runner’s body has failed to perform cellular respiration.
the runner’s cells are relying completely on aerobic respiration.
the runner’s muscles have accumulated carbon dioxide.

After several miles of running and sprinting in intervals, the runner’s muscles ache and feel fatigued because the runner's muscles have accumulated lactic acid.

As a result of the high lactate levels there is an increase in the acidity of the muscle cells  and disruptions of other metabolites, and also in burning sensation often felt in active muscles.

they absorb it i think

not sure

you

and after water is usually warmed by the sun the water temperature raises and then evaporates .