QUESTION 1 
 Scientists were able to determine the age of the Earth from rock samples that were analyzed. What technique was used to do this? 
 A. geologic time scale 
 B. radiometric dating 
 C. fossil records 
 D. extinction
 QUESTION 2 
 What is the best description of organisms of the Precambrian era? 
 A. land plants and animals 
 B. dinosaurs and primitive mammals 
 C. single-celled organisms and soft, boneless animals 
 D. ferns and flying reptiles 
 QUESTION 3 
 What is the present geological era? 
 A. Cenozoic 
 B. Mesozoic 
 C. Paleozoic 
 D. Precambrian 
 QUESTION 4 
 Which era is known as the Age of Mammals? 
 A. Cenozoic 
 B. Mesozoic 
 C. Paleozoic 
 D. Precambrian 
 QUESTION 5 Which era is known as the Age of Reptiles? 
 A. Cenozoic 
 B. Mesozoic 
 C. Paleozoic 
 D. Precambrian