The precambrian era makes up about 90% of the earths history, but there was little to no living organisms at the time other than microscopic ones. The first eukaryotes were found in the cambrian period after the precambrian period, not only that but at the end of the precambrian era in the Proterozoic era there was a mass extinction of about 70-80% of all living organisms
Answer:
Compositional Layers
Layer Depth
Crust 0-100km silicates
Mantle 100-2900km iron and magnesium silicates
Core 2900-6370km metals
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The brain and the skull the skull protects the brain
<span>skin, hair, nails, hope this helps</span>
