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: What makes one species provide us with a bunch of different meal options?, Context: Interspecific crop diversity is, in part, responsible for offering variety in what we eat. Intraspecific diversity, the variety of alleles within a single species, also offers us choice in our diets. If a crop fails in a monoculture, we rely on agricultural diversity to replant the land with something new. If a wheat crop is destroyed by a pest we may plant a hardier variety of wheat the next year, relying on intraspecific diversity. We may forgo wheat production in that area and plant a different species altogether, relying on interspecific diversity. Even an agricultural society which primarily grows monocultures, relies on biodiversity at some point.

SOLUTION: the variety of alleles

PROBLEM: What was the original direction of the cannons?, Context: Unveiled in 1888, Royal Arsenal's first crest featured three cannon viewed from above, pointing northwards, similar to the coat of arms of the Metropolitan Borough of Woolwich (nowadays transferred to the coat of arms of the Royal Borough of Greenwich). These can sometimes be mistaken for chimneys, but the presence of a carved lion's head and a cascabel on each are clear indicators that they are cannon. This was dropped after the move to Highbury in 1913, only to be reinstated in 1922, when the club adopted a crest featuring a single cannon, pointing eastwards, with the club's nickname, The Gunners, inscribed alongside it; this crest only lasted until 1925, when the cannon was reversed to point westward and its barrel slimmed down.

SOLUTION:
northwards