The Cambrian explosion that lasted approximately 10 million years brought an abundance of multicellular life.
It did not bring - any plants, any animal groups that we think of today, such as: mammals, reptiles, birds, insects, and spiders. The fish that appeared in the Cambrian were unlike any fish alive today.
It did bring some early transistional animals such as lobopods ( basically worms with legs )which are intermediate between arthropods and worms.
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