Which material is not a form of pyroclastic material?
a. volcanic dust
b. volcanic dirt
c. volcanic bombs
d. lapilli

Where is the world’s shortest commercial runway?

Scientists think that convection currents flow in earth’s a. continents. b. mantle. c. lithosphere. d. inner core.

All of the following came out of china and were exchanged along the silk road, except a. papermaking b. block printing c. buddhism d. compasses select the best answer from the choices provided a b c d