What can you learn from this photograph about this part of earth surface

What border separates sonora and chihuahua national border state border physical boundary natural boundary

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.

Who were the kelvin-rus? describe who influenced them.