The second paragraph of the article discusses how scientists monitored a crack in a rock face on a cliff. How did their findings help them assess the risk of falling rock?
Step-by-step explanation:
The scientists discovered that the crack expanded and contracted about 1 centimeter each day based on daily changes in temperature. They also discovered that the overall gap in the rock widened over the span of several summers and weakened the rock. The instability of this weakened rock might increase the risk of rock falls.