Ana studied a diagram of the geologic timeline to complete her homework assignment She became curious about the different divisions that formed the sections of an era. What is the name for the groups into which eras are divided?
Mesozoic Era
Triassic
Jurassic
Cretaceous
Began
(Millions of
years ago)
252
201
145
Duration
(Millions of
years ago)
51
56
79
sections
B. periods
o o o o
C. divisions
D
Precambrian