Final answer:
The Aztec Empire expanded in the mid-fifteenth century and absorbed most of the Mayan Empire. They built the capital city of Tenochtitlán and made advancements in agriculture and urban development.
Step-by-step explanation:
The empire that expanded in the mid-fifteenth century and absorbed most of the Mayan Empire was the Aztec Empire. The Aztecs, who dominated southern Mexico, expanded outward from their base in central Mexico and created a vast empire. They built the capital city of Tenochtitlán which had a population of 100,000 people. The Aztecs subjugated other groups, required taxes and tributes, and made advancements in agriculture and urban development.