Question

Which accomplishment of some early American civilizations indicates that they had knowledge of astronomy?

Answer 1

the development of a 365-day calendar I think

Answer 2

The Mayan and Aztec were the early American civilizations who knew astronomy. Carrying detailed tables of calculating periods of the Moon, eclipses, and the occurrence Venus. The Maya calendar was based on the Pleiades star clusters, the Sun, the Moon, and other planets. The Mayan has always given importance to Venus and Mars.

The Aztec were known as people of the sun their first calendar is one of 365 days based on the solar year.