Which of the following statements about the spinal nerves is true?

The statement that spinal nerves consist of both motor and sensory fibers is accurate because spinal nerves are mixed nerves formed by the union of dorsal (sensory) and ventral (motor) roots. Each spinal nerve carries sensory information from the body to the central nervous system, as well as motor commands from the central nervous system to the muscles. This dual functionality allows for a coordinated response to stimuli and contributes to the body's reflex actions, making the mixed nature of spinal nerves essential for normal locomotion and bodily functions.

Dorsal rootlets are responsible for bringing sensory information to the spinal cord, while ventral rootlets contain motor fibers that exit the spinal cord to innervate muscles. Therefore, the correct answer reflects the comprehensive role that spinal nerves play in the nervous system, encompassing both sensory input and motor output.