1. interaction between humans and the environment
2. development and interaction of cultures
3. state-building, expansion, and conflict
4. creation, expansion, and interaction of economic systems 5. development and transformation of social structures.

which best categorizes “racial and ethnic constructions”?

2. Development and interaction of cultures.

Hope this helps! 
Good Luck~

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.