Input: Article: A 2013 study in Nature reported that DNA found in the 24,000-year-old remains of a young boy from the archaeological Mal'ta-Buret' culture suggest that up to one-third of the indigenous Americans may have ancestry that can be traced back to western Eurasians, who may have "had a more north-easterly distribution 24,000 years ago than commonly thought". "We estimate that 14 to 38 percent of Native American ancestry may originate through gene flow from this ancient population," the authors wrote. Professor Kelly Graf said,

Now answer this question: When was a study about the DNA of a young boy published in Nature?

Output: 2013

Input: Article: Symbiotic relationships include those associations in which one organism lives on another (ectosymbiosis, such as mistletoe), or where one partner lives inside the other (endosymbiosis, such as lactobacilli and other bacteria in humans or Symbiodinium in corals). Symbiosis is also classified by physical attachment of the organisms; symbiosis in which the organisms have bodily union is called conjunctive symbiosis, and symbiosis in which they are not in union is called disjunctive symbiosis.

Now answer this question: What is an example of ectosymbiosis?

Output: mistletoe

Input: Article: Other city states formed federated states in self-defense, such as the Aetolian League (est. 370 BCE), the Achaean League (est. 280 BCE), the Boeotian league, the "Northern League" (Byzantium, Chalcedon, Heraclea Pontica and Tium) and the "Nesiotic League" of the Cyclades. These federations involved a central government which controlled foreign policy and military affairs, while leaving most of the local governing to the city states, a system termed sympoliteia. In states such as the Achaean league, this also involved the admission of other ethnic groups into the federation with equal rights, in this case, non-Achaeans. The Achean league was able to drive out the Macedonians from the Peloponnese and free Corinth, which duly joined the league.

Now answer this question: When was the Aetolian League formed?

Output:
370 BCE