D abiotic means its not in biology
251 million years ago, the Permian extinction occurred. It is the widest and most massive extinction that wiped out 85-90% of marine species and 70% of land vertebrates at that time. There were recorded low oxygen levels in deep and shallow oceans, extreme shift in the carbon cycle, massive eruption of a basal salt volcano in Siberia and the consecutive global warming that occurred evidently ended early prehistoric life.
Answer:
<u>Why do geologists use the geologic time scale?</u>
Because of the time span of Earth's past is so great, geologist use geologic time scale to show Earth's history.
<u>What is the geologic time scale?</u>
The geologic time scale is a record of the geologic events and the evolution of life forms as shown in the fossil record.
<u>How do scientists develop the geologic time scale?</u>
Scientists first developed the geologic time scale by studying rock layers and index fossils worldwide. With this information,scientists placed Earth's rocks in order by relative age. Later, radioactive dating helped determine the absolute age of the divisions in the geologic time scale.
<u>What do the divisions of geologic time scale depend on?</u>
The divisions of the geologic time scale depend on events in the history of life on Earth.
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