Answer:
neur/o
Step-by-step explanation:
The root word "neur/o" (with or without the o) means nerves of the brain. The rest of the word is "algia" which is the medical term for pain. A prefix is the beginning or the first root of a word and the suffix is the end of a word. Therefore, the prefix is neur- and the suffix is -algia, making the word neuralgia... which means nervous system pain, pain in the brain, or pain in the nerves/nervous system.