 
 <prompt> Wetin dey burrow for ground? Based on di last question, write one context wey contain di answer. E fit be 1 - 20 sentences. Context: <response>: Some paleontologists dey suggest say animals don dey exist since long before the Cambrian explosion, possibly reach 1 billion years ago. Trace fossils like tracks and burrows wey dem find for the Tonian period dey show say triploblastic worms, like metazoans, wey dey roughly as large (about 5 mm wide) and complex as earthworms don dey exist. During the beginning of the Tonian period wey happun around 1 billion years ago, dem notice say Stromatolite diversity reduce, wey fit mean say grazing animals don show face, since stromatolite diversity increase when grazing animals go extinct for the End Permian and End Ordovician extinction events, and reduce shortly after the grazer populations recover. But the discovery wey show say tracks wey dey very similar to these early trace fossils dey produced today by the giant single-celled protist Gromia sphaerica dey make people doubt their interpretation as evidence of early animal evolution. 