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

Both Eras and Periods measure time after the start of the Cambrian Period, which means that your answer is:

C.

Hope it helped,

BioTeacher101

Answer 2

The correct answer is option C, that is, eras and periods both appear at the start of the Cambrian period.

The first geological time period of the Paleozoic Era is known as the Cambrian period. This period ended for approximately 53 million years and signifies a dramatic burst of evolutionary modifications in life on Earth also called Cambrian Explosion.

The Cambrian period signifies an essential phase in the history of life on Earth. It is the phase when the majority of the prime animal groups initially appeared in the fossil record. An era refers to a particular time period, while a period may be used to signify towards the events, which do not exhibit any particular era or precise dates.