In which direction did heavier materials mostly move inside Earth?

Correct answer: Towards the centre

In the early history of Earth, gravity separated materials according to their density. Heavier substances, such as iron and nickel, tended to sink inward, while lighter materials moved toward the outer layers. This process is called differentiation and helped form Earth’s layered structure. The concentration of heavy materials at the centre contributed to the formation of the core, while lighter materials became part of the mantle and crust.

Option A is correct because gravity pulled the denser materials towards Earth’s centre. They did not move into outer space or simply collect in the atmosphere or on ocean surfaces. The question concerns the interior of the young Earth, where melting and movement allowed materials to separate. Remembering the simple rule—dense materials sink and lighter materials rise—explains both the direction and the later formation of the core.