Answer:
Motor Cortex
Explanation:
According to my research on studies conducted by various medical professionals, I can say that based on the information provided within the question Professor Kim is stimulating the motor cortex of his participants brain. This is because the Motor Cortex is the part of the brain whose main function is controlling all the signals that go to our bodies causing our limbs to move. Which is why the participants arm moved when it was stimulated.
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