A) humans descending from early primates
B) vertebrates moving onto land in the Paleozoic
C) canine-bearing marsupials in Australia and wolves in North America
D) the Cambrian explosion
A) Excessive amount of salt on roads in winter
B) Abundant salt-water spray from the Atlantic Ocean
C) Past salt extraction
D) Presence of salt in the subsurface
E) Options a and b
A) rise in sea level
B) rise in atmospheric oxygen
C) ecological changes
D) a major meteorite impact
E) change in seawater chemistry
A) indicate the age of the individual
B) are a growth structure
C) separate septa
D) options a and b
E) options b and c
A) Meteorite impact
B) Snowball Earth glaciations
C) Regression
D) Transgression
E) Predators
A) in a broad shallow sea
B) in a deep sea trench
C) represent a graptolite facies
D) on the side of a volcano
E) none of the above
A) apatite
B) calcium carbonate
C) silicate
D) native iron
A) appearance of organisms with shells, spines, and hard skeletons
B) active rifting within most continents
C) low sea level
D) spread of lush vegetation on land
A) at the bottom of a deep lake
B) on a coral reef
C) on a beach
D) in the deepest parts of the oceans
E) beneath a glacier
A) more oxygen is available at hydrothermal vents
B) deep water would protect early life from ultraviolet radiation
C) cold water found at hydrothermal vents would encourage development of bacteria
D) lightning would provide an energy source at hydrothermal vents
A) Ridge-push and slab-pull forces
B) Subduction zones
C) Convection in the mantle
D) Options a and b
E) Options a and c
A) convergent plate boundaries
B) divergent plate boundaries
C) strike-slip plate boundaries
D) none of the above
A) true
B) false
A) under the north pole
B) under the south pole
C) at tropical latitudes
D) about where it is now
A) True
B) False
A) occurred at the peak of the last glaciation
B) occurred at the end of meteorite bombardment
C) occurred in the Proterozoic
D) occurred in the Cambrian
A) conglomerate
B) granite
C) quartz-rich sandstone
D) feldspar-rich breccia
A) 3.8 billion years
B) 2.5 billion years
C) 1.5 billion years
D) 540 million years
E) 270 million years
A) a late Proterozoic supercontinent
B) a type of radioactive decay
C) a moon of Jupiter
D) an early Cambrian organism
A) An organelle of eukaryotic cells
B) a type ofsediment on the Martian surface
C) a carbonate deposit
D) a gas-generated lava texture
A) 4,2,3,1
B) 1,3,2,4
C) 2,3,4,1
D) 2,3,1,4
A) A decrease in greenhouse gases in the atmosphere
B) An increasing distance from the sun
C) A marked decrease in the albedo
D) evolution of the Ediacaran fauna
E) none of the above
A) on oceanic islands
B) on continental margins
C) at mid-ocean ridges
D) near subduction zones
E) in the centers of continents
A) did not exist
B) were covered by lush tropical forests
C) were barren of vegetation
D) hosted a rich variety of land animals
E) none of the above
A) 4.5 billion years ago
B) 2-2.5 billion years ago
C) 545 million years ago
D) 65 million years ago
E) 2 million years ago