The big feasts and celebrations that took place.
Answer:
A. a separate part of a city dedicated largely to one group
Explanation:
The enclaves represent separate parts of the cities where one group is dominant. This often happens with the migrants, as very often they look to live next to compatriots so that they can communicate and have easier adaptation in the new place. Unfortunately, the enclaves make lot of problems, as the people living in them often don't even try to integrate, but keep their own culture, speak their own language, set their own rules, which results in divisions on ethnic or religious basis.
The Colorado River was like otherwise rivers but due to overuse for it's water to humans and agriculture and also with the poor manegnent of the river, The rivers has become an environmental problems, Threatening species around the river that Daily depended on the vezitation and fresh water it got from the river. The river is expected to have it's water flow cut completely soon so that will also mean the shut down of hydroelictric dams.
I hope I was a help.