1. The youngest rocks on the ocean floor are located ____.
near continents
at mid-ocean ridges
far from mid-ocean ridges
near Asia
2. The presence of the same ____ on several continents supports the hypothesis of continental drift.
fossils
rocks
neither a nor b
both a and b
3. The boundary between two plates moving together is called a ____.
divergent boundary
convergent boundary
transform boundary
lithosphere
4. Bands of rock on the seafloor showing alternating magnetic orientation indicate Earth's magnetic field has ____.
reversed itself in the past
weakened
become stronger
remained the same
5. Scientists believe that differences in ____ cause hot, plastic-like rock in the asthenosphere to rise toward Earth's surface.
density
magnetism
weight
composition
6. Active volcanoes are most likely to form at ____.
transform boundaries
divergent boundaries
the center of continents
convergent oceanic–continental boundaries
7. Earthquake waves are called ____.
seismic waves
convergent waves
divergent waves
wave amplitudes
8. Which statement is true of P-waves?
They travel the fastest through rocks.
They vibrate at 90° to the wave motion.
They are last to reach the epicenter.
They are the most damaging.
9. The Richter scale is based on measurements of the ____ of a seismic wave.
)
speed
frequency
intensity
amplitude
10. Molten rock beneath Earth’s surface is called ____.
magma
tephra
lava
pyroclasts
11. A composite volcano ____.
sometimes erupts violently
is steep-sided
is composed of alternating layers of lava and tephra
all of the above
12. Determining the order of events and the relative age of rocks by examining the position of rocks in a sequence is called ____.
absolute dating
radiometric dating
relative dating
radiocarbon dating
13. In a series of undisturbed rock layers where shale lies between sandstone below and limestone above, the ____.
limestone is youngest
shale is youngest
sandstone is youngest
beds are all the same age
14. The longest subdivision in geologic time is a(n) ____.
epoch
period
century
eon
15. Cenozoic Era life-forms include ____.
humans
reptiles
marine mammals
all of the above
16. The end of the Paleozoic Era was signaled by ____.
the development of humans
mass extinction of land and sea animals
the development of organisms with hard parts
both a and b
17. Angiosperms are the dominant land plant today because they developed ____.
deep root systems
hard seed coats
large, broad leaves
heavy, thick bark
18. ____ is a process by which organisms with characteristics suited to the environment will survive and reproduce.
Natural selection
Artificial selection
Evolution
Organic evolution
i need help with this so dont tell me i shouldnt be getting help i know what im doing so plz just help with the answers thanks
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May 16th, 2009 at 2:02 pm
1. Mid Ocean Ridges, it is the location where plates are spreading and molten material is deposited in the rift where it cools and forms rock
2. Both fossils and rocks that are similiar on far away coasts suggests that at one time those two coasts were connected but drifted apart.
3. Convergent boundary, two plates are converging. Plates moving away are Divergent (diverging) and along side each other are Transform boundaries.
4. Reversed itself, The magnetic record in rocks so that the magnetized particles have reversed their orientation on occassion. This is observed because the particles could only record the magnetic polarity when molten, before they soldified. Once solid the magnetism is set for posterity.
5. Density causes material to rise, what ever is more bouyant will "float" to the surface and deposit on the crust. Composition would affect density, but if only one composition deposited then we would not see so many varieties of rock deposition at the same geologic time period.
6. Look up the Ring of Fire. Convergening boundaries between oceans and continents cause the oceanic plate to plunge under the continental plate, the oceanic material is heated to melting and because it is less dense it rises to the crust where the pressure is vented onto the surface in the form of a volcano.
7. seismic waves are the form that energy from the force of an earthquake travels through the earth.
8. P waves travel fastest through rock, I believe the Swaves cause the shaking that is damage causing. Also P waves travel allong the axis of wave motion (parallel) where S-waves travel perpendicular to the wave. Last to reach the epicenter would be the S wave because the P wave travels faster. The focus is the point of origin of the earth quake, the epicenter is the center of that focus on the surface of the earth (think epidermis for skin). Since P waves travel faster through rock, they would reach the surface first.
9. The Richter scale is a base-10 logarithmic scale obtained by calculating the logarithm of the combined horizontal "amplitude" of the largest displacement from zero on a Wood–Anderson torsion seismometer output.