Biology

The type of cell that should have the MOST mitochondria is muscle cells in the legs of a marathon runner.

Muscle cells, especially those in highly active tissues like the legs of a marathon runner, require a tremendous amount of energy (ATP) to sustain prolonged physical activity. To meet this high energy demand, they contain a large number of mitochondria to efficiently produce ATP through cellular respiration.

The other options are less likely to have as many mitochondria:

Photosynthetic cells in tree leaves: These cells primarily rely on chloroplasts for energy production through photosynthesis, though they still have mitochondria. ...