Question

select the statement that is most correct.
ganglia are collections of neuron cell bodies in the spinal cord that are associated with
efferent fibers.
the dorsal root ganglion is a motor - only structure.
ganglia associated with afferent nerve fibers contain cell bodies of sensory neurons.
the cell bodies of afferent ganglia are located in the spinal cord.

Explanation:

1. Analyze the first option: Ganglia are collections of neuron cell bodies outside the CNS (spinal cord and brain), and efferent (motor) neuron cell bodies in the CNS are in nuclei, not ganglia in the spinal cord. So this is incorrect.
2. Analyze the second option: The dorsal root ganglion contains cell bodies of sensory (afferent) neurons, not motor neurons. So it's not a motor - only structure. This is incorrect.
3. Analyze the third option: Ganglia associated with afferent (sensory) nerve fibers (like the dorsal root ganglion) do contain the cell bodies of sensory neurons. This statement is correct.
4. Analyze the fourth option: The cell bodies of afferent ganglia (e.g., dorsal root ganglion) are located outside the spinal cord (in the dorsal root ganglion, which is adjacent to the spinal cord but not inside it). So this is incorrect.

Answer:

Ganglia associated with afferent nerve fibers contain cell bodies of sensory neurons.