The answer to the question would be nearly parallel to the shoreline.
Answer: While building the city Tenochtitlan on the islands of lake Texcoco, the Aztecs faced swampy lands with no foundations and soil that was bad for farming.
Explanation: Because the islands in lake texcoco did not have very solid ground, the Aztecs had trouble building their city. They overcame these challenges by building canals to reroute the water.
1. They Allies set the terms for the Japanese surrender at the Potsdam Conference
As far as I am concerned Gao was not one of the Songhay Empire's major ones but I bet two answers should be acceptable in this question. I also think that you can include the third option from the scale represented above because <span>Algiers were quite far away on north so they couldn't be the part of the Songhay. </span>