Final answer:
Sensory neurons in Molly's skin send signals to the CNS when her feet are burned. The CNS processes this information and sends a command to her muscles to run into the ocean.
Step-by-step explanation:
The scenario described involves various neurons and their functions. When Molly's feet are burned by the hot sand, sensory neurons in her skin send electrical signals to the central nervous system (CNS) to convey this information. The CNS processes this information in the cerebral cortex, integrating it with other sensory stimuli, emotions, and memories. Finally, a plan is developed and a command is sent to her muscles to run into the ocean and cool her feet off.