Final answer:
The cell bodies of efferent neurons are located in the ventral horn of the spinal cord.
Step-by-step explanation:
The cell bodies of efferent neurons, which are responsible for sending signals from the central nervous system to the muscles for contraction, are located within the ventral horn of the spinal cord. These neurons are also known as lower motor neurons and have a corona of dendrites surrounding the cell body with an axon that extends out of the ventral horn through the ventral root to join the spinal nerve. Such multipolar motor neurons are important for the output to skeletal muscles, allowing voluntary and reflexive movements.