<h2>540 million years ago
</h2>
Paleozoic.
Era immediately follows Precambrian It lasted about 4.5 billion years.
When did abundant fossil evidence first appear in the geologic record.
540 million years ago.
<span> i think it's the gene pool</span><span>
</span>
The first step the biologist needs to make an observation in which to create a hypothesis.
Hope this was helpful!
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