Answer:
This refers to the Cambrian period, a geological time, at around 570 - 510 million years ago. It is when invertebrate life first appeared.
During the period comes what is known as the Cambrian Explosion - where the fossil record suddenly seems to radiate with an array of multi-celled creatures.
During the period comes what is known as the Cambrian Explosion - where the fossil record suddenly seems to radiate with an array of multi-celled creatures.
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