Final answer:
A loosely organized fighting force that makes surprise attacks is characteristic of guerrilla warfare.
Step-by-step explanation:
A loosely organized fighting force that makes surprise attacks is characteristic of guerrilla warfare. Guerrilla warfare is a form of irregular warfare where small, unconventional forces use tactics such as ambushes, sabotage, and hit-and-run attacks to target a larger, more organized enemy. These surprise attacks give the guerrilla fighters an advantage and allow them to disrupt the enemy's operations.