I want to know the answer to the following question:
When was the period where the majority of multicellular phyla first appeared?
All the background I'm provided with is that "The Phanerozoic eon (the last 540 million years) marked a rapid growth in biodiversity via the Cambrian explosion—a period during which the majority of multicellular phyla first appeared.". Is that enough to answer the question?
Answer: yes