One of the most distinctive characteristics of the Woodland and Mississippian cultures were the largest: - earthen mounds
- pottery vases
- trade routes
- rotundas

A characteristic of the Woodland and Mississippian cultures was the earthen mounds.

Explanation:

The Woodland and Mississippian cultures were the most advanced cultures in what is now the USA. They had well-developed civilizations in comparison to the people groups in their surroundings. Their trademark though was the construction of earthen mounds that are found all over the territories in which the two cultures existed.

The earthen mounds, as the name suggests, are mounds made out of the ground. They vary in size, from just a few meters to hundreds of meters. Their shapes too vary, with some being in a semi-circular shape, some like bulges, while some even like snakes. The purpose of these mounds is still a theme of hot debate, but it is most commonly thought that they had religious purposes.