Final answer:
The term 'nociceptors' refers to free nerve endings with large receptive fields that detect pain in the skin.
Step-by-step explanation:
The term 'nociceptors' refers to D. free nerve endings with large receptive fields that detect pain in the skin. Nociceptors are specialized sensory receptors that are responsible for detecting and transmitting signals related to pain. These receptors are located throughout the skin and are activated by various harmful or damaging stimuli, such as heat, pressure, or chemicals.