How much energy is released during fermentation?

In animal cells,like muscle,during exercise when $O_{2}$ is inadequate for cellular respiration,pyruvic acid is reduced into lactic acid by

If fermentation is allowed to proceed in a closed vessel, what will happen?

In mature mammalian erythrocytes,the respiration is

How many $ATP$ molecules are obtained from the fermentation of $1$ molecule of glucose?

Radha was running on a treadmill at a great speed for $15$ minutes continuously. She stopped the treadmill and abruptly came out. For the next few minutes,she was breathing heavily/fast. Answer the following questions.
$(a)$ What happened to her muscles when she did strenuous exercise?
$(b)$ How did her breathing rate change?