Why did the area of Mesopotamia have such deep and complex culture found in it in the late ancient times?

In what the Greeks later called Mesopotamia, Sumerians invented new technologies and perfected the large-scale use of existing ones. In the process, they transformed how humans cultivated food, built dwellings, communicated and kept track of information and time.

Explanation:

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.

the tallest building in the western hemisphere and the sixth tallest building in the world