Volcanic ash is a good geologic time marker because the ash

•  is deposited rapidly over a large area
•  spreads evenly in all compass directions
•  is easily weathered and eroded
• remains in the atmosphere for millions of years

The change in life-forms in the fossil record from less complex organisms to more complex organisms over time is best explained by

• extinction 
• evolution 
• dynamic equilibrium
• original horizontality

The graph shows the yearly air temperature and precipitation of a location on Earth.  This location would be most likely at a latitude of

• 0°
• 35° S 
•  50° N
•  90° N

Arrows in the diagram represent the daytime flow of air over a coastal region.  Which process primarily transfers heat by moving air?

• conduction
• convection
• radiation 
• transpiration 

The graph shows the radioactive decay of rubidium-87.  What percentage of rubidium-87 atoms will be left after four half-lives?

• 25.0%
• 12.5%
• 6.25% 
• 3.125% 

The pressure at the interface between Earth’s outer core and inner core is inferred to be

• 0.2 million atmosphere
• 1.5 million atmospheres
• 3.1 million atmospheres
• 3.6 million atmospheres

Which type of tectonic plate boundary is found between the South American Plate and the Scotia Plate?

• transform
• convergent
• divergent 
•  complex or uncertain

The epicenter of an earthquake was located 1800 kilometers from a seismic recording station. If the S-wave arrived at the seismic station at 10:06:40 a.m., at what time did the P-wave arrive at the same seismic station?

• 10:03:00 a.m. 
• 10:03:40 a.m. 
• 10:09:40 a.m.
• 10:10:20 a.m.

A strong earthquake that occurs on the ocean floor could result in the formation of

•  a tsunami 
•  a delta 
• an El Niño event
• an ocean current

 The block diagram represents a rapid downslope flow of saturated soil and rock layers.  What are two likely causes of this rapid downslope flow?

• groundwater and abrasion
• groundwater and gravity
• prevailing wind and abrasion
• prevailing wind and gravity