Question

natural selection and evolution 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 long intervals of geologic time and periods are smaller subdivisions within eras. They are not independent as periods are part of eras. Also, eras are not more recently established than periods and eras have a larger time - span than periods. The Cambrian period is part of the Paleozoic era, and eras and periods existed before and after the Cambrian period.

Answer:

None of the above options are correct.