Mayan astronomers were known for the development of a system for determining the rise and fall of the tides. measuring distance between stars. predicting eclipses of the sun and moon. calculating the distance between Earth and moon.

Predicting eclipses of the sun and moon

Explanation:

Astronomers always gazed up into the night sky and stared at eclipses all through the centuries.

The Aztecs and the Mayans studied eclipses using various numerical methods, and could foresee exactly if another one might occur. They might actually have predicted a recent solar eclipse with tiny margins of error.

The correct answer is option C, a rushing river
Explanation:
Canyons are formed as of the erosional activities of both wind and water affecting a huge plateau, mountain or hill. These plateaus, mountains, and hills are formed due to tectonic movements.
During the course of time, snow on the plateau melts and pull down half a million tons of sediments along with it. This sediment carrying river cuts the plateau thereby forming the Canyons