Well if you mean what does the controlled part of a scientific investigation, it is the part of the investigation that will be your control or your base, untouched, original, data and such.
<span>The correct answere for this question is A - the three major types of volcanoes are shiel volcanoes, cinder volcanoes and composite volcanoes. Two other tyypes of volcano are the lava dome volcano, and the Rhyolite Caldera complex (this type is not common, but are the most dangerous and explosive - Yellowstone is an example of this type of volcano).</span>
Answer:
oceanic crust sinks because it is denser and has higher specific gravity than the more silicon aluminum enriched continental crust. What drives substitution is convection and conduction in outer core of earth, that heat , only a small part of which is due radioactive isotopes, has to make it's way to Earth's surface by both conduction and convection. Iron and nickel o have the highest specific gravities of the 10 most common elements in the Milky Way Galaxy. This is why oceanic crust sinks and is subducted continental crust has to have a lot more force applied before it inks, because it doesn't want to sink.
