Which makes up the smallest span in the Geologic Time Scale?

a. Mesozoic era
b. Paleozoic era
c. Cenozoic era
d. Precambrian Time

1 answer

The correct answer is d. Precambrian Time, which includes the Hadean, Archean, and Proterozoic eons, is the longest and earliest span in the Geologic Time Scale, covering over 4 billion years. The Paleozoic, Mesozoic, and Cenozoic eras are all more recent and shorter in duration.