Answer:
The formation of a glacial trough involves two processes abrasion and plucking. Abrasion is when pieces of debris in the glacier wear away at the rocks below, a bit like sandpaper. The sharper rocks in the ice can also cause scratches in the rocks called striations.
Explanation:
The main mechanism through which the layering happened is gravity: it pulled the heavier, denser material to the center, leaving the less dense material on the surface.
The material that was on the outside cooled quicker, but this was the result, not the cause.
The answer is
<span>2) Gravity caused more-dense material to move toward the center of each planet.</span>
