The size of the motor area in the brain for any specific body part is relative to:

A) the rest of the body.
B) its position in the body.
C) the complexity of its movements.
D) the number of muscles it contains.
E) the area of the brain that controls it.

The size of the motor area in the brain dedicated to a specific body part is directly related to the complexity of movements that part can perform, not merely its size or the number of muscles it contains. This is why areas like the hands and face have disproportionately large representations in the motor cortex.