Which statements explain why independent city-states emerged in ancient Greece?

Choose all answers that are correct.

A.

Trade between the different city-states enhanced communication.

B.

Rivers provided a means of navigable travel and communication.

C.

Some city-states were located on isolated islands.

D.

The seas were sometimes difficult to navigate and limited communication.

One thing was that Seas were sometimes difficult to navigate which limited communication - D. this was already a factor which limited the possibility of one united Greece emergin because it made it very difficult to talk to these isolated islands that couldbe found through the difficult-to-navigate seas.

Another thing was that C - some city-states were located on isolated islands.