15. How much did each stone weigh in the Stonehenge? a. Less than 5 tons
b. 50 pounds
c. Over 50 tons

Marine exptoration of oil uses seismic waves to locate oil in the seabed. what is a negative impact from seismic waves on the aquatic ecosystem of the ocean? a. seismic waves kill microoganisms b. seismic waves disrupts the sand and causes seafloor erosion c. seismic waves have virtually no adverse affects on marine life d. seismic waves damage the sonar that dolphins and whales use to orient themselves underwater

15 points to the "charlemagne" section, what were the two policies that charlemagne implemented when he took the throne? what was the result of the policies and how did it impact his warriors?

Which of the follow modern activities would only have been possible after the neolithic revolution