The Following Questions Refer to the Description and Figure Below

question 85

Multiple Choice

The following questions refer to the description and figure below.
The figure represents a cross section of the sea floor through a mid-ocean rift valley, with alternating patches of black and white indicating sea floor with reversed magnetic polarities. At the arrow labeled "I" (the rift valley) , the igneous rock of the sea floor is so young that it can be accurately dated using carbon-14 dating. At the arrow labeled "III," however, the igneous rock is about 1 million years old, and potassium-40 dating is typically used to date such rocks. NOTE: the dashed horizontal arrows indicate the direction of sea-floor spreading, away from the rift valley.
Figure 25.1
-A major evolutionary episode that corresponds in time most closely with the formation of Pangaea was the

• A)origin of humans.
• B)Cambrian explosion.
• C)Permian extinctions.
• D)Pleistocene ice ages.
• E)Cretaceous extinctions.