About 1.2 billion years ago, eukaryotic and multicelled organisms evolved because

oxygen became available from cyanobacteria

banded iron formations developed

meteorite impacts increased

the atmosphere got thicker from volcanic outgassing

What was the first official pair of sister cities?

What was on result of the potato famine

Which of the following statements does not describe shi huangdi? a. shi huangdi was the first emperor of the qin dynasty. b. shihuangdi wrote the lunyu, the most important text in confucianism. c. shihuangdi conquered city-states to unite china. d. shihuangdi began the process of building the great wall of china.