Final answer:
The nurse is assessing the sensory tract of the nervous system when placing a vibrating tuning fork on a patient's wrist or ankle.
Step-by-step explanation:
When a nurse places a vibrating tuning fork on a patient's wrist or ankle, they are assessing the sensory tract of the nervous system. This is because the tuning fork stimulates the sensory receptors in the skin and sends signals through the sensory pathways of the spinal cord to the brain, allowing the patient to feel the vibrations.