In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

From what era, once thought devoid of animal life, was evidence of grazer populations discovered?, Context: Some paleontologists suggest that animals appeared much earlier than the Cambrian explosion, possibly as early as 1 billion years ago. Trace fossils such as tracks and burrows found in the Tonian period indicate the presence of triploblastic worms, like metazoans, roughly as large (about 5 mm wide) and complex as earthworms. During the beginning of the Tonian period around 1 billion years ago, there was a decrease in Stromatolite diversity, which may indicate the appearance of grazing animals, since stromatolite diversity increased when grazing animals went extinct at the End Permian and End Ordovician extinction events, and decreased shortly after the grazer populations recovered. However the discovery that tracks very similar to these early trace fossils are produced today by the giant single-celled protist Gromia sphaerica casts doubt on their interpretation as evidence of early animal evolution.
the Tonian period

Which artist is listed  first, Context: Similarly, movies and television often revert to standard, clichéd snatches of classical music to convey refinement or opulence: some of the most-often heard pieces in this category include Bach´s Cello Suite No. 1, Mozart's Eine kleine Nachtmusik, Vivaldi's Four Seasons, Mussorgsky's Night on Bald Mountain (as orchestrated by Rimsky-Korsakov), and Rossini's William Tell Overture.
Bach

The journey of the body is immortalized in?, Context: Years before his death, Genghis Khan asked to be buried without markings, according to the customs of his tribe. After he died, his body was returned to Mongolia and presumably to his birthplace in Khentii Aimag, where many assume he is buried somewhere close to the Onon River and the Burkhan Khaldun mountain (part of the Kentii mountain range). According to legend, the funeral escort killed anyone and anything across their path to conceal where he was finally buried. The Genghis Khan Mausoleum, constructed many years after his death, is his memorial, but not his burial site.

legend