City council brings development to the local people
It can be one of the more powerful private groups as well.
Yes, City councils and town boards generally consist of several (usually somewhere between 5 and 50) elected aldermen or councillors. 
They govern the city and government area
That is true. Some places calls it Local Governement or council 
The difference between these city councills tend to varie.
That is true. They duties varies from place to place
They all have a large amount of power though.