#1 Yuan Dynasty unified China after a period of more than 300 years. ...
#2 The first paper currency to be used predominantly was Yuan's official banknote Chao.
#3 Yuan astronomer Guo made the most accurate calendar built till then in China.
#5 Novel was developed as a literary form.
A. Cause orbit contains space
To be honest I think answer is two
Cyanobacteria, also known as "blue-green algae", are the unicellular organisms which are able to produce oxygen.
Approximately 540 years ago, the atmosphere was very poor on oxygen. Cyanobacteria are thought to be responsible for the oxidization of the atmosphere back then, in an event known as <em>"The Great Oxygenation Event"</em>. As a result, Earth's life forms suffered drastic changes in their composition, as they evolved from being <em>anaerobic</em> to becoming organisms <em>highly dependant</em> on oxygen. The oxygenation of the atmosphere would eventually provide the adequate environment in order for the <em>Cambrian Explosion</em>, or the first diversification of living organisms, to happen.
The main issue that divided colonial society in South Carolina during the 1700s was that of slavery and indentured servitude. Some people thought that it was unfair for whites, having to "compete" for labor positions.
