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

[Q]: 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.
[A]: the Tonian period

[Q]: Where is the Centennial Light?, Context: The relationships above are valid for only a few percent change of voltage around rated conditions, but they do indicate that a lamp operated at much lower than rated voltage could last for hundreds of times longer than at rated conditions, albeit with greatly reduced light output. The "Centennial Light" is a light bulb that is accepted by the Guinness Book of World Records as having been burning almost continuously at a fire station in Livermore, California, since 1901. However, the bulb emits the equivalent light of a four watt bulb. A similar story can be told of a 40-watt bulb in Texas that has been illuminated since 21 September 1908. It once resided in an opera house where notable celebrities stopped to take in its glow, and was moved to an area museum in 1977.
[A]: a fire station

[Q]: What was one of the events that helped lead to the deaths of 20 million people: Dungan Revolt or The First Sino-Japanese War?, Context: The reign of the Qianlong Emperor (17351796) saw the apogee and initial decline in prosperity and imperial control. The population rose to some 400 million, but taxes and government revenues were fixed at a low rate, virtually guaranteeing eventual fiscal crisis. Corruption set in, rebels tested government legitimacy, and ruling elites did not change their mindsets in the face of changes in the world system. Following the Opium War, European powers imposed unequal treaties, free trade, extraterritoriality and treaty ports under foreign control. The Taiping Rebellion (185064) and Dungan Revolt (186277) in Central Asia led to the deaths of some 20 million people. In spite of these disasters, in the Tongzhi Restoration of the 1860s, Han Chinese elites rallied to the defense of the Confucian order and the Qing rulers. The initial gains in the Self-Strengthening Movement were destroyed in the First Sino-Japanese War of 1895, in which the Qing lost its influence over Korea and the possession of Taiwan. New Armies were organized, but the ambitious Hundred Days' Reform of 1898 was turned back by Empress Dowager Cixi, a ruthless but capable leader. When, in response to the violently anti-foreign Yihetuan ("Boxers"), foreign powers invaded China, the Empress Dowager declared war on them, leading to defeat and the flight of the Imperial Court to Xi'an.
[A]:
Dungan Revolt