Which of the following issues is the most significant challenge facing the people of the middle east today? a. dust storms b. freezing temperatures c. earthquakes d. water scarcity

Middle east doesn't have large deserts, so no dust storms. It doesn't get that cold in Middle East as far to my knowledge. There's no fault line, so no earthquakes either. This leaves you with Water Scarcity which makes sense because it's an arid and dry area, so water is, in fact, scarce.

Tenochtitlán was the capital of the aztec empire. it was a busy and bustling city where“there are daily more than 60,000 souls, buying and selling, and where are found all the kinds of merchandise produced in these countries.” when cortes arrived in 1519, theenormity of the trading market and the smoothness of it’s running both surprised and  impressed him.