Answer:
They are important. they prevent one section of gov from taking all the power.
Explanation:
Answer: D. advanced technology in irrigation to create agricultural surpluses
Explanation:
There is no map so I do not know which river valley civilization you speak of but I found the options for this question with the answer above being the most likely answer.
The question most probably alludes to the Indus River Valley Civilization which is one of the oldest civilizations to ever exist in the human world.
They had quite a high population for the time and so came up with various technological advances to cater for their people including sewage and water systems.
It was their work with irrigation that earned them high praise however. They came up with advanced irrigation techniques which ensured that agriculture boomed and created enough food to feed the population.
They could be separated by mountains or rivers and could be influenced by neighboring peoples.
