1.what theory was supposed by alfred wegener that the earth was once made up of a single large mass called pangaea?
a.Wegener's theory
b.plate tectonic theory
c.continental drift theory
d.seafloor spreading theory
2.which of the following is NOT an observation that supports seafloor spreading theory?
a.depth of the ocean
b.locations of glacial deposits
c.thickness of seafloor sediments
d.magnetization of the oceanic crust
3.why does plate tectonic theory considered as the unfying theory?
a.because it explains the puzzle-fit of continents
b.because it explains the mechanism of continental drift
c.because it shows evidences from thermal energy trends in the mantle
d.because it combines continental drift,saefloor spreading and other supporting data
4.which of the following increases the distance from a mid-ocean ridge?
a.the depth of the sea floor
b.the edge of oceanic lithosphere
c.the thickness of the lithosphere
d.all of the choices were correct
5.what causes the movement of the ithospheric plate?
a.the density of the plate
b.convection current in the mantle
c.the magnetic force at the pole
d.the temperature at the ,mantle