C. They are based on evidences obtained from investigation
the Soviet union was communist
The atmosphere and Earth's interior are layered by density. Gravity pulls more strongly on denser materials so denser materials are at the center of things. Earth's core, at its center, is denser than its crust.
The presence of U-shaped valleys is the best evidence that glaciers one covered an area. The correct answer is B, U-shaped valleys.
Answer:
a bar-built estuary and a coastal plain
Explanation:
