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