Question

Why is the fact that earth was molten liquid in its early stages the most important event in history

Answer 1

It was important because it tells why the denser material had sunken and the lighter is floating on the surface.

Explanation:

Eventually, after around 500 million years, our young planet's temperature warmed to the liquefying purpose of iron—about 1,538° Celsius (2,800° Fahrenheit). This crucial crossroads in Earth's history is known as the iron fiasco. The iron fiasco permitted more prominent, progressively quick development of Earth's liquid, rough material.

We also know that at one point all the material in the planet was molten because the denser material had sunk and the lighter was floating.