Lack of cooperation with more advanced civilizations.
Answer:
Factory owners could pay children less money than they paid adults.
Explanation:
As for the rivers, the colonists were aware you must have water to successfully maintain life whether it be human life or plant life, it is necessary. Also being close to water helped them in the workforce, like carrying out trade or fishing It was a "win win" for them.
When they started to build an empire around the Mediterranean but wasn't until about the 6th century I believe. Hope I helped
