What does an unconformity in a sequence of rock layers reveal about geologic history? a. a rock layer must have turned upside down. b. a layer of rock might have eroded. c. the layers must cover hundreds of square miles. d. the layers must have been deposited very quickly.

the answer is b. hope this !

heat released by collision processes during accretion, and heat from decay of radioactive elements

explanation:

true. earthquakes are felt whenever there is a slip around a fault in the rocks below the earth. this reorientation of faults create sesmic waves and is known as earthquake, the severity of which is measured in richter scale. these are more prominent in hilly regions as the rocks usually form faults to balance the pressures on it.