Final answer:
The three major types of neurons are sensory, motor, and interneurons, functioning as signal carriers and processors in the nervous system.
Step-by-step explanation:
The three major types of neurons are: a) Sensory, motor, and interneurons. Sensory neurons carry nerve impulses from tissues and organs to the spinal cord and brain, effectively translating external stimuli into signals the nervous system can understand. Motor neurons transmit commands from the brain and spinal cord to muscles and glands, prompting action. Interneurons are the connectors; they carry nerve impulses between sensory and motor neurons, playing a crucial role in the processing of information within the nervous system.