What did Genghis Khan’s sons do after they took over his empire? They led their own wars to expand the size of the empire.
They prevented one another from crossing into each other’s territory.
They sent their soldiers to the capital to support the Great Khan.
They governed the divided empire so badly that the people revolted.

They led their own wars to expand the size of the empire

Explanation:

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in contrast, the biological controls are self-sustaining, inexpensive and very effective once established. biological control could be used on thousands of golf course acres, improving their biodiversity and quality as wildlife habitat. in the process, the golf industry will be shown to be leaders in an environmental stewardship program of benefit not only to the lands they manage but also to the watersheds in which they exist.

b. major john c. frémont led a rebellion called the bear flag revolt.

explanation:

during the bear flag revolt, from june to july 1846, a small group of american settlers in california rebelled against the mexican government and proclaimed california an independent republic. the republic was short-lived because soon after the bear flag was raised, the u.s. military began occupying california, which went on to join the union in 1850. the bear flag became the official state flag in 1911.