What must be presented on a rock that undergoes frost wedging?

A. A crack
B. Round shape
C. Holes around it
D. Sharp edges

A. A crack

To determine what must be presented on a rock that undergoes frost wedging, let's first understand what frost wedging is. Frost wedging is a type of mechanical weathering caused by the expansion of water upon freezing. When water freezes, it expands, exerting pressure on its surroundings. This pressure can cause rocks to crack or break apart.

Now, considering this information, the answer to the given question would be:

A. A crack.

As water seeps into the cracks or joints in rocks, and then freezes and expands, it exerts pressure on the rock, causing it to crack open or widen existing cracks. Over time, this process can lead to the breakdown of rocks into smaller pieces.

Therefore, to identify a rock undergoing frost wedging, you would expect to see a crack or cracks on the rock's surface.