I want to know the answer to the following question:
In which era, did the first phylum of multicellular organisms appear?
All the background I'm provided with is that "The history of biodiversity during the Phanerozoic (the last 540 million years), starts with rapid growth during the Cambrian explosion—a period during which nearly every phylum of multicellular organisms first appeared.". Is that enough to answer the question?
Answer: yes