Part 2. The following 8 short essay questions are designed to evaluate critical thinking/reasoning skills, please make sure that you provide the most detailed answer you can.  You do not need to answer all of the questions.  What you need to do is choose 2 the following questions to answer (correctly number which questions you chose). (5 pts. each)  1) The Nebular Hypothesis explains how Earth formed through various phases of accretion and differentiation.  Explain in your own words why differentiation of Earth is the most significant event in Earth’s history.  2) The Earth system includes the Biosphere, Lithosphere, Atmosphere, and Hydrosphere.  Pick two of those spheres and briefly discuss how a change in one will result in change in the other.  Focus your answer on how the spheres interact with one another (Hint: think about the concept of plate tectonics).  3) In your own words, explain why the theory of plate tectonics is considered the grand unifying theory in geology.  Keep in mind geologic features such as rift valleys, mountain ranges, faults, fossils, and other related phenomena.  4) What is the definition of a mineral and why is that definition so important to the methods used to identify minerals and how humans utilize minerals?  5) Explain the rock cycle (in detail) and explain in your own words how each rock type can form and whether or not the rock cycle has to have a single starting point.  6) We now know that seismic waves have provided knowledge about multiple processes/aspects of Earth.  What are at least three of the major areas of Geology that seismic studies have helped advance and how did these studies advance those fields of study?  7) What is the difference between passive and active continental margins in regards to the continental shelf, slope, and rise?  Why does the difference exist?  8) How has ocean floor mapping/investigations changed since the late 1800s? What have these new methodologies allowed for in regards to economic potential?

Bonus Question – How do the compositions of rocky and gaseous planets differ?

True or False; Around most of the Atlantic the continental slope descends into an oceanic trench and associated volcanism, but around the Pacific the continental slope merges with a more gently sloping continental rise?

Fossil evidence linking the Gondwana continents includes the:

Plate tectonic processes have influenced:

Bonus Question –  Isotopes of the same element have:

Which is NOT associated with a mid-oceanic ridge? 

True or False; The best characteristic to use when identifying minerals is color?

The Big Bang took place approximately ____ years ago.

Bonus Question –  The composition of the mantle is: