Physical Science: Earth Movement [true fale/multiple]?

[Joshy C]

im homeschooled & i'm not catchin on to these +its spring break, -so if anyone wants to HELP thanks -dont go out of your way to be rude not wanted.
[True/False]
11.Mid-Ocean ridges are the result of sinkin convection currents of the mantle.

13.There is a rock cycle where rocks can return to the magama.

17.a soild under great pressure could be made to flow

18.isostasy is stronger than buoyancy because it causes mountians to float.

Multiple Choice-
Plate tectonics is a ___.
a.theory, b.myth, c.hoax, d.fact, e.hypothesis
[i put hypothesis from what i read sounded true]

39.Melted plate material reappears by way of____.
a.folds, b.fault blocks, c.volcanoes, d.ocean trenches, e.non of these

40.what theory explains the origin of volcanones, earthquakes, mid-ocean ridge, ocean trenches, and mountain ranges.
a.gravity, b.plate tectonics, c.evolution, d.earth crust, e.rocks

--i guess that kinda goes hand in hand with 39

thhhhhanks guys =]