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

SOLUTION: the Tonian period

PROBLEM: Who can remove the plague?, Context: A number of non-Greek etymologies have been suggested for the name, The Hittite form Apaliunas (dx-ap-pa-li-u-na-aš) is attested in the Manapa-Tarhunta letter, perhaps related to Hurrian (and certainly the Etruscan) Aplu, a god of plague, in turn likely from Akkadian Aplu Enlil meaning simply "the son of Enlil", a title that was given to the god Nergal, who was linked to Shamash, Babylonian god of the sun. The role of Apollo as god of plague is evident in the invocation of Apollo Smintheus ("mouse Apollo") by Chryses, the Trojan priest of Apollo, with the purpose of sending a plague against the Greeks (the reasoning behind a god of the plague becoming a god of healing is of course apotropaic, meaning that the god responsible for bringing the plague must be appeased in order to remove the plague).

SOLUTION: god of plague

PROBLEM: What was happening as the Greeks fled Asia?, Context: In the aftermath of the First World War, Greece attempted further expansion into Asia Minor, a region with a large native Greek population at the time, but was defeated in the Greco-Turkish War of 1919–1922, contributing to a massive flight of Asia Minor Greeks. These events overlapped, with both happening during the Greek genocide (1914-1922), a period during which, according to various sources, Ottoman and Turkish officials contributed to the death of several hundred thousand Asia Minor Greeks. The resultant Greek exodus from Asia Minor was made permanent, and expanded, in an official Population exchange between Greece and Turkey. The exchange was part of the terms of the Treaty of Lausanne which ended the war.

SOLUTION:
Greek genocide

