Answer:
During the years of the Black Plague, very few places in Europe had safe drinking water. Most people had to obtain their water from more or less unclean sources, although a few were lucky enough to live in sparsely populated areas with non-existant pollution, or close to pristine water sources like a stream.
The lack of safe drinking water, or better, the abundance of dirty water sources also contributed to spread of the disease in the 14th century, which killed around a third of the European population at the time, in some places killing over half of the population.
Answer:
B- opened borders to all foreigners that wished to visit China.
Answer:
B. Roman Republic Established-->Julius Caesar Assassinated-->Caesar Augustus becomes emperor-->Western Roman Empire Falls
Explanation:
The Roman Republic was established, then Julius Caesar names himself Dictator of Rome and is assassinated by the senate, Caesar Augustus, someone close to Julius then becomes the first Emperor, and years later when Rome split into Eastern and Western Rome, germanic migrations and attacks cause the Western Roman Empire to fall
The Chernobyl nuclear catastrophe.