Question

Which best describes eras and periods?
A. Eras have a smaller time span than periods.
B. Eras and periods are independent of each other
C. Eras and periods both appear at the start of the Cambrian period.
D. Eras were more recently established on the time scale than periods.

Answer 1

i think that the answer is (c) eras and periods both appear at the start of the cambrian period.

hope it helps .

thanks.