Which of these is the most likely explanation for the information depicted in the map?
a) ohio was not admitted to the union until 1870
b) people were migrating from southern to northern states.
c) western expansion spread the u. s. population over a wider area.
d) the world wars resulted in dramatic population shifts in the u. s.

a mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics. this uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary.a geomagnetic reversal is a change in a planet's magnetic field such that the positions of magnetic north and magnetic south are interchanged.