How do compositional differences between oceanic and continental crust affect Earth's topography?
Well the oceanic crust is composed mainly of Basalt, which is thinner than continental granite but denser. Continental crusts granite is thicker but less dense.
The process of sea floor spreading?
Well, molten rock is pushed up to the surface where it cools to form hot, buoyant rock. This then pushes the existing rock near the vent away keeping the new rock closest to the vent. spreading the sea floor.
At what type of plate boundaries would you expect to find crust formation? what about destruction?
Divergence creates new crust (underwater volcanoes) Convergence is possibly due to the fact that it melts rock and convergence is when one shelf sinks under the other into the mantle.
How can plate tectonic motion affect ocean circulation and climate?
Plate tectonic motion can affect ocean circulation by affecting the distribution of warm and cold currents, such as in the Gulf Stream.
How does sea floor spreading rates affect global sea level?
If the sea floor spreading is fast then the water level stays relatively even. More young hot crust. If the sea floor spreading is slow, it creates an overall low basin and lower sea level.
How can changing sea levels affect biotic interaction? Biotic isolation?
The sea level can affect where there is more primary productivity. It can isolate movement for organisms and isolate environments.