Why was Inca vulnerable at the time of Pizarros arrival?

The Inca Empire was vulnerable at the time of Francisco Pizarro's arrival due to a combination of internal strife and recent civil war, which had weakened their central authority and resources. Additionally, the empire was still recovering from the devastating effects of a smallpox epidemic that had spread prior to Pizarro's arrival, significantly reducing their population and military strength. These factors, along with the Spanish's advanced weaponry and tactics, made the Inca susceptible to conquest.