Who proved the earth was round

Name the two rivers that run through the fertile crescent. how were the rivers both positive and negative to societies of the fertile crescent?

The inner planets mercury, venus, earth, and mars were formed by

Tides are caused by a differences in the gravitational force of the sun at different points on earth. differences in the gravitational force of the moon at different points on earth differences in earth’s gravitational field strength at different points on earth’s surfac fluctuations in the gravitational attraction between earth and the moon.