Correct Answer: Human muscle cells

Solution : The correct option is Human muscle cells .

The breakdown of pyruvate into lactic acid and energy in the absence of oxygen takes place in human muscle cells. This process is called anaerobic respiration. When there is not enough oxygen available, muscle cells convert pyruvate into lactate to produce a small amount of ATP, the energy currency of cells. This process allows muscle cells to continue to function for a short period, even when oxygen is limited.