Science

2. ridge /any of several seismically active submarine mountain ranges that extend through the Atlantic, Indian, and South Pacific oceans: each is hypothesized to be the locus of seafloor spreading.
5. the sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate.
7. boundary / is a type of fault whose relative motion is predominantly horizontal, in either a sinistral (left lateral) or dextral (right lateral) direction.
10. / is a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement as a result of rock mass movement.
11. valley / is a linear-shaped lowland between several highlands or mountain ranges created by the action of a geologic rift or fault.
12. Drift / the lateral movement of continents resulting from the motion of crustal plates.

1. boundary /is an actively deforming region where two (or more) tectonic plates or fragments of the lithosphere move toward one another and collide.
3. boundary / is a linear feature that exists between two tectonic plates that are moving away from each other.
4. tectonics /a theory explaining the structure of the earth's crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates that move slowly over the underlying mantle.
5. spreading /a process in which new ocean floor is created as molten material from the earth's mantle rises in margins between plates or ridges and spreads out.
6. trench /any long, narrow, steep-sided depression in the ocean bottom in which occur the maximum oceanic depths, approximately 7,300 to more than 11,000 metres (24,000 to 36,000 feet).
8. /the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.
9. /the hypothetical landmass that existed when all continents were joined, from about 300 to 200 million years ago.