Final answer:
Dorsal roots contain sensory fibers from the dorsal root ganglia, while ventral roots contain motor fibers from motor neurons in the spinal cord's anterior horn.
Step-by-step explanation:
The fibers found in the dorsal roots are strictly sensory in function. They consist of the axons of sensory neurons, which originate from the dorsal root ganglia and enter the spinal cord through the dorsal nerve root. These fibers carry sensory information from the periphery to the central nervous system (CNS).
On the other hand, the fibers present in the ventral roots are strictly motor in function. These fibers are the axons of motor neurons in the anterior horn of the spinal cord, which exit the spinal cord through the ventral nerve root and send action potentials to skeletal muscles, causing them to contract in the target regions.