Final answer:
The descending tracts originate from the Motor cortex and the brainstem. These tracts include the corticobulbar and corticospinal tracts which carry motor commands to the lower motor neurons in the central nervous system. The correct answer is C) Motor cortex and brainstem.
Step-by-step explanation:
Descending tracts originate from what two areas of the brain? The correct answer is C) Motor cortex and brainstem. The descending tracts refer to the nerve fibers in the central nervous system that carry motor commands from the brain to the spinal cord or periphery.
Specifically, the neurons located in the primary motor cortex, also known as Betz cells, synapse with lower motor neurons in the brain stem or in the spinal cord. Major descending pathways include the corticobulbar tract and the corticospinal tract. These tracts originate in the cortex and have targets in the brainstem and spinal cord, respectively. The correct answer is C) Motor cortex and brainstem.