Scientists believe that is an example of an internal force that changes the earth’s crust.
a. mining
b. plate tectonics
c. human development
d. erosion

One of the main reasons societies settled along rivers in the neolithic era was because a) the village elders demanded it. b) the land there was more valuable. c) it was more safe and secure there. d) it provided irrigation for farming.

After considering options, a student using the problem-solving process should next

Which of the following types of nonrenewable fuel sources requires the storage of radioactive waste? a. coal b. nuclear c. solar d. oil