The environment plays a crucial role in an organism's ability to fossilize. Which is the best location for fossilization?
A) bottom of a river 
B) very dry environments, such as land 
C) bottom of a lake covered by sediment 
D) an environment exposed to natural elements 
True or False: If a geologist found two fossils of different species buried next to each other in a rock layer, he or she might hypothesize that the two organisms may have been alive during the same time period.
A) True 
B) False 
C) Neither
Fossil A is found in a rock layer above a layer containing Fossil B. Which fossil is probably older?
A) Fossil A 
B) Fossil B 
C) both are the same 
D) can't be determined 
What is the half-life of strontium-90?
A) 112 years 
B) 84 years 
C) 56 years 
D) 28 years