The geological study of rocks around a previously active volcano ____.
a. is of scientific interest but does not aid eruption prediction
b. is complicated by the effects of erosion
c. concentrates on the study of tuff layers, with little other useful information
d. can detect chemical changes in rocks caused by carbon dioxide emissions
e. can only identify sites of lava flows
Question 2
Carbon dioxide ____.
a. is not dangerous due to its strong odor
b. is a danger in a volcanic area even when no eruption is imminent
c. tends to collect in the attic of houses when no eruption is imminent
d. is only a danger during periods of volcanic activity
e. is a particular danger to climbers and hikers since it is emitted at the summit of a volcano