Question

the main, or central, idea of the passage is genghis khan ruled with fear and might, while kublai khan governed with regard for the people he ruled. how does the detail in bold develop the main idea?
mongol leader genghis khan was one of the worlds most formidable conquerors. born around 1162, genghis amassed an army of thousands of men and united the nomadic tribes of mongolia under his rule. next, he turned his attention to central asia and china. using brilliant military tactics—and extreme cruelty—he expanded the mongol empire to an area approximately the size of africa. kublai khan, genghiss grandson, conquered china and was a powerful leader in his own right. yet unlike his grandfather, kublai is remembered for governing his acquired territories fairly, rather than dominating them with military might. instead of exploiting the people of china, kublai sought to accommodate and embrace chinese culture. he became the first mongol to rule over all of china, and he founded the countrys yuan dynasty.
it draws a contrast between the two leaders styles of governance.
it casts doubt on kublai khans leadership abilities.

Explanation:

The bolded detail "Yet unlike his grandfather, Kublai is remembered for governing his acquired territories fairly, rather than dominating them with military might" clearly shows a contrast. It highlights that Genghis Khan used military might (fear and might) to rule, while Kublai Khan used a fair - governing approach (regard for the people). This directly supports the main idea of contrasting their governance styles. The second option "It casts doubt on Kublai Khan's leadership abilities" is incorrect as the text actually presents Kublai Khan's leadership in a positive light (governing fairly, embracing culture etc.).

Answer:

It draws a contrast between the two leaders' styles of governance.