Answer:5.4*10^8years ago
Explanation: Cambrian explosion which is also referred to as CAMBRIAN RADIATION caused the divergence of majority of Metazoans( multicellular and Eukaryotic organisms with Mitochondria and differentiated cells,tissues and Organs,they evolved from Phylum protists over 700million years ago) It lasted for about thirteen to 25million years ago,this details were obtained from fossil records. This explosion took place about five hundred and fourth one(541) million years ago.
