Question

a. tectonics b. erosion c. mining d. subduction

Explanation:

The Grand Canyon was formed over millions of years as the Colorado River cut through the land. This process is known as erosion, which is the wearing - away of rock and soil by natural agents like water, wind, and ice. In this case, the river's flowing water gradually removed rock and sediment, carving out the canyon.

Answer:

B. erosion