Answer:
Our solar system began as a collapsing cloud of gas and dust over 4.6 billion years ago. Over the next 600 million years, called by geologists the Hadean Era, the sun and the planets were formed, and Earth's oceans were probably created by cometary impacts.
<span>A peasant rebel rounded up troops and defeated Qin forces.</span>
Hoover Dam, it provided western United States with much electricity
