Final answer:
The posterior 1/3rd of the spinal cord transmits signals via unmyelinated axons located in the gray matter, which predominantly convey sensory information to the brain.
Step-by-step explanation:
The posterior 1/3rd of the spinal cord transmits signals via unmyelinated axons. This region of the cord is important for processing sensory information. Signals are transmitted through the gray matter of the spinal cord, which is composed of neuron and glial cell bodies, as well as interneurons that connect two neurons located in different parts of the body. Specifically, axons and cell bodies in the dorsal spinal cord convey mostly sensory information from the body to the brain.