How were the Maya and the Aztecs alike?

A. They built vast road networks to unite conquered lands.
B. They organized into independent city-states.
C. They paid a labor tax to a single emperor.
D. They adapted challenging terrain to support farming.

To determine how the Maya and the Aztecs were alike, we can look at the different options given and find the ones that apply to both civilizations.

Option A states that they built vast road networks to unite conquered lands. This is true for the Maya civilization. They constructed a sophisticated network of roads that connected different cities and regions within their empire. However, there is limited evidence to suggest that the Aztecs had a similar road network, so this option cannot be used to show their similarity.

Option B states that they organized into independent city-states. This is true for both the Maya and the Aztecs. Both civilizations were divided into numerous city-states that were largely independent of one another. Each city-state had its own government, ruling elites, and economic centers.

Option C states that they paid a labor tax to a single emperor. This applies only to the Aztecs. The Aztec empire was centralized and ruled by a single emperor. The cities and provinces within the empire paid a labor tax, known as the "tribute," which supported the emperor and the elite.

Option D states that they adapted challenging terrain to support farming. This applies to both the Maya and the Aztecs. Both civilizations developed sophisticated agricultural techniques to farm in challenging landscapes, such as constructing terraces, canals, and raised fields, to maximize agricultural productivity.

Based on these considerations, the correct answer is B. They organized into independent city-states and D. They adapted challenging terrain to support farming.