Answer:
Hunting and gathering caused a more nomadic lifestyle, where they were always moving where their food was, and farming, otherwise known as the Agricultural Revolution, was made so we could advance civilization and our technology. These were made into villages and were later made into city-states like Ur and Uruk.
Explanation:
The factors that made it difficult for Eastern Europe to improve its water quality were outdated sewer systems, raw water quality, worn-out water utilities and unskilled employees. So we can say that four options given in the question fits the bill perfectly. These basic infrastructural reasons were responsible for being a hurdle towards improving the water quality. <span />
Two accomplishments of Aristotle included discovering and proposing the fifth element, <span>aether, which rounded out the five elements, and he also pioneered the study of zoology.</span>
As the sectional crisis over California intensified in 1850,
>> <span>D Southern states considered leaving the Union. </span>
