Why are rocks an imperfect record of the history of the planet?
a. rocks can be easily misplaced
b. earth is dynamic and the record erodes
c. rocks are inherently untrustworthy
d. it is impossible to know the age of a rock
e. all rocks are the same age
what is a surface of erosion or nondeposition?
a. a conformity
b. a fossil bed
c. if moss covered a nice place for a nap
d. a hiatus
e. an unconformity