When new clay sediment is deposited on top of old beach material, it's known as
a. regression.
b. progression.
c. aggression.
d. transgression.

Sediment is a material found at the bottom of the ocean which is subsequently transported by the action of wind , water, ice and by the force of gravity acting on the particles. They are broken down by processes of weathering and erosion. Marie regression is the process wherein the areas submerged seafloor are exposed above the sea level. A marine transgression is an event during which the sea level rises with respect to the land and the shoreline moves toward higher ground that results in flooding. The answer is letter D.

Answerair masses develop near the equator are warm; tropical air mass