Question

which best describes eras and periods? eras were more recently established on the time scale than periods. eras have a smaller time span than periods. eras and periods both appear at the start of the cambrian period. eras and periods are independent of each other.

Explanation:

In geological time - scale, eras are larger - scale divisions than periods. Eras are composed of one or more periods. They are not independent of each other. Eras have a larger time - span than periods and were not more recently established on the time - scale than periods. The Cambrian period is part of the Paleozoic era, and eras and periods have existed long before the start of the Cambrian.

Answer:

None of the given options are correct.