Tidal ranges will be greatest when the Earth and the Moon are at their closest distance.
The Moon with it's gravitational field, pulling force, causes the water on Earth to rise, on the part faced towards the Moon, and to retreat, on the part of the Earth that is not faced towards the Moon. The closer the Earth and the Moon are, the bigger the influence from the Moon and the Earth's surface waters, thus the bigger the tidal range.
External migration means immigrate to a country from another country
Option b the United steps test gets its long needed independence
Density currents are caused by changing density.