Living Environment Regents Practice Test 2026 – Complete Exam Prep

The increase in the number of mitochondria in brain cells of rats during treadmill training highlights the relationship between physical exercise and cellular adaptation. Mitochondria are known as the powerhouses of the cell because they are responsible for producing ATP, the energy currency of the cell. When animals engage in regular physical activity, such as treadmill training, their energy demands increase, prompting cells, including those in the brain, to enhance their capacity for energy production.

This adaptation allows the brain to better support various functions, especially those that require high energy levels, such as maintaining neuronal health, promoting neurogenesis, and supporting synaptic plasticity. The increase in mitochondrial density can lead to improved overall brain function and better cognitive performance. Therefore, the correct response focuses on the significance of mitochondria in energy production and their adaptive response to exercise.