Q: You are presented with the quiz "What is a form of mechanical weathering?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "ice wedging is when ice causes rocks to crack by expanding in openings" and "ice wedging is the most important form of mechanical weathering". So, what's the best answer to the question?

Pick your answer from:
+microbes breaking down rock.
+By coral exoskeletons.
+wind and erosion.
+oxygen breaking down rock.
+ice expanding in rock openings.
+removal of rock by acid rain.
+remains of prehistoric life.
+fissures of hot, acidic water.
The answer is:
ice expanding in rock openings