1. along which features does seafloor spreading occur?
a. fault lines
b. mid-ocean ridges
c. ocean basins
d. ocean trenches
2. which statement identifies a major reason for the subduction that to form volcanoes?
a. the release of hot ash and steam in a pyroclastic flow
b. the unusually high temperature at hotspots
c. the upwelling of magma between diverging plates
d. the difference in density of oceanic and continental plates
3. ocean trenches form over millions or billions of years. which statement accurately describes how ocean trenches form?
a. two plates of continental crust slide past each other
b. a plate of oceanic crust is subducted under a plate of continental crust
c. two plates of oceanic crust pull away from each other
d. a plate of continental crust collides with another plate of continental crust
4. which features do most stratovolcanoes and cinder cone volcanoes have in common?
a. violent eruptions and thin, flowing lava
b. broad base with quiet eruptions
c. wide dome shape and thick lava
d. steep sides and violent eruptions
5. why is no land created or destroyed at transform boundaries?
a. because the plates crumble into each other at these boundaries
b. because magma rushes into gaps at these boundaries
c. because the plates are more dense at these boundaries
d. because the plates only slip past each other at these boundaries
6. geologists observed signs of widespread ancient glaciers from the same time period in areas across south america, africa, antarctica, india, and australia. what theory did this observation support?
a. most of earth was once covered in a vast ice sheet.
b. glaciers were once more common than they are today.
c. those continents were once together as one supercontinent.
d. earth was much farther than the sun than it is today.
my answers are\\ a, d, b, a, c, d i really need