Final answer:
The 1st-order neurons of the spinothalamic tract are indeed sensory nerve endings with cell bodies located in a DRG, which is true. These neurons synapse with second-order neurons in the spinal cord, whose axons cross to the opposite side and travel to the thalamus.
Step-by-step explanation:
The statement that the 1st-order neurons of the spinothalamic tract are sensory nerve endings with cell bodies located in a dorsal root ganglion (DRG) is true. These first-order neurons of the spinothalamic tract indeed begin at the sensory nerve endings and have their cell bodies in a DRG. They extend their axons into the dorsal horn of the spinal cord, where they synapse with the second-order neurons.
The second-order neurons' cell bodies are located in the spinal cord gray matter, and their axons decussate (cross) within the spinal cord and then ascend to the thalamus. Finally, the third-order neurons in the thalamus project to the cerebral cortex, completing the pathway that carries pain and temperature sensations to the brain.