How does north China compare to south China with regard to rainfall and farmable land

What do the discoveries of shells used in jewelry and a huge dredged canal tell us about the indus valley civilization?

What role did imperialism play in world war 2

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