When the earth’s surface gets weathered away over time, it is known as:

That would just be called Weathering and Erosion. Erosion happens when rocks and sediments are picked up and moved to another place by ice, water, wind or gravity. Mechanical weathering physically breaks up rock. One example is called frost action or frost shattering. Water gets into cracks and joints in bedrock.

Answera discharge of static electricity;

The figure is not necessarily a parallelogram because only one diagonal is bisected and only one pair of sides is congruent.