Which of the following best describes the impact of glaciers upon the surface of the earth?
a. ice buried continents under a few hundred feet of ice.
b. glaciers scraped across the surface and altered landscapes and the course of rivers.
c. the passage of glaciers created new ecosystems.
d. all of the above.

The correct answer is b. Glaciers scraped across the surface and altered landscapes and the course of rivers.

This is the option that best the describes the influence of the glaciers though the other two are also correct statements. Glaciers have and still are creating lots of landforms, from minor to ones that are hundreds of kilometers long. They have created lots of valleys, horns, fjords, and also some relief forms like glacial terraces, rocky rivers, rocky ponds etc. Because of their valleys lots of rivers have been affected and have changed their course because the glacial valleys are usually the easiest way for the water to run through.