Problem: Extract the answer to the question from the following context. Question: What is Chicago known for? Context: Theoretical analyses show that detours that increase flight distance by up to 20% will often be adaptive on aerodynamic grounds - a bird that loads itself with food to cross a long barrier flies less efficiently. However some species show circuitous migratory routes that reflect historical range expansions and are far from optimal in ecological terms. An example is the migration of continental populations of Swainson's thrush Catharus ustulatus, which fly far east across North America before turning south via Florida to reach northern South America; this route is believed to be the consequence of a range expansion that occurred about 10,000 years ago. Detours may also be caused by differential wind conditions, predation risk, or other factors.

A: wind

Problem: Extract the answer to the question from the following context. Question: What happened in the 13th year of the century known as the 2000's? Context: Nigeria was the only country in Africa to have never eradicated polio, which it periodically exported to other African countries; Polio was cut 98% between 2009 and 2010. However, a major breakthrough came in December 2014, when it was reported that Nigeria hadn't recorded a polio case in 6 months, and on its way to be declared Polio free. In 2012, a new bone marrow donor program was launched by the University of Nigeria to help people with leukaemia, lymphoma, or sickle cell disease to find a compatible donor for a life-saving bone marrow transplant, which cures them of their conditions. Nigeria became the second African country to have successfully carried out this surgery. In the 2014 ebola outbreak, Nigeria was the first country to effectively contain and eliminate the Ebola threat that was ravaging three other countries in the West African region, the Nigerian unique method of contact tracing employed by Nigeria became an effective method later used by countries, such as the united States, when ebola threats were discovered.

A: a new bone marrow donor program was launched by the University of Nigeria

Problem: Extract the answer to the question from the following context. Question: What is the name of the road that, for a time, is both B3 and B6 in the same span? Context: The Schnellweg (en: expressway) system, a number of Bundesstrae roads, forms a structure loosely resembling a large ring road together with A2 and A7. The roads are B 3, B 6 and B 65, called Westschnellweg (B6 on the northern part, B3 on the southern part), Messeschnellweg (B3, becomes A37 near Burgdorf, crosses A2, becomes B3 again, changes to B6 at Seelhorster Kreuz, then passes the Hanover fairground as B6 and becomes A37 again before merging into A7) and Sudschnellweg (starts out as B65, becomes B3/B6/B65 upon crossing Westschnellweg, then becomes B65 again at Seelhorster Kreuz).

A: Sudschnellweg

Problem: Extract the answer to the question from the following context. Question: What is the difference in DST between the United Kingdom and mainland Chile? Context: Beginning and ending dates are roughly the reverse in the southern hemisphere. For example, mainland Chile observed DST from the second Saturday in October to the second Saturday in March, with transitions at 24:00 local time. The time difference between the United Kingdom and mainland Chile could therefore be five hours during the Northern summer, three hours during the Southern summer and four hours a few weeks per year because of mismatch of changing dates.

A:
Beginning and ending dates are roughly the reverse