Active Volcanos!

Shan C asked:


Multiple Choice
1. The youngest rocks on the ocean floor are located ____.
(1 point)

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.
(1 point)

fossils

rocks

neither a nor b

both a and b

3. The boundary between two plates moving together is called a ____.
(1 point)

divergent boundary

convergent boundary

transform boundary

lithosphere

4. Bands of rock on the seafloor showing alternating magnetic orientation indicate Earth’s magnetic field has ____.
(1 point)

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.
(1 point)

density

magnetism

weight

composition

6. Active volcanoes are most likely to form at ____.
(1 point)

transform boundaries

divergent boundaries

the center of continents

convergent oceanic–continental boundaries

7. Earthquake waves are called ____.
(1 point)

seismic waves

convergent waves

divergent waves

wave amplitudes

8. Which statement is true of P-waves?
(1 point)

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.
(1 point)

speed

frequency

intensity

amplitude

10. Molten rock beneath Earth’s surface is called ____.
(1 point)

magma

tephra

lava

pyroclasts

11. A composite volcano ____.
(1 point)

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 ____.
(1 point)

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 ____.
(1 point)

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) ____.
(1 point)

epoch

period

century

eon

15. Cenozoic Era life-forms include ____.
(1 point)

humans

reptiles

marine mammals

all of the above

16. The end of the Paleozoic Era was signaled by ____.
(1 point)

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 ____.
(1 point)

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.
(1 point)

Natural selection

Artificial selection

Evolution

Organic evolution

Short Answer
19. Glacial deposits often form at a high latitude near the poles. Explain why glacial deposits have been found in Africa.
(3 points)

20. What is a seismic-safe structure? List two things that would help a building become seismic-safe.
(3 points)

Figure 9-1

21. List events A–F shown in Figure 9-1 in the order that they occurred, beginning with the oldest event.
(3 points)

22. If horizontal layers of sedimentary rock have a vertical fault running through them, how might a geologist use relative dating to determine when the fault occurred?
(3 points)

Problem
23. A sample of a radioactive element has a mass of 80 g. How much parent and daughter materials are in the sample after two half-lives?
(3 points)

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