Why does a small percentage of the country's population live in China's West?

Due to unfavorable climate and soil for farming and production, Western China is not conducive to living. Due to this, China's western regions are sparsely populated compared to other parts of China, where production and farming are more conducive.

The eastern, coastal provinces are much more densely populated than the western interior because of the historical access to water.

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.