Extract the answer to the question from the following context. Question: What is the one thing speculated about bird navigation? Context: The timing of migration seems to be controlled primarily by changes in day length. Migrating birds navigate using celestial cues from the sun and stars, the earth's magnetic field, and probably also mental maps.
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Answer: mental maps

Extract the answer to the question from the following context. Question: In the English Language, a word used to describe an action are classified as what? Context: The infinitive form ends in t (archaically, ti). It is the form found in dictionaries and the form that follows auxiliary verbs (for example, muzu te slyset"I can hear you"). Czech verbs have three grammatical moods: indicative, imperative and conditional. The imperative mood adds specific endings for each of three person (or number) categories: -/-i/-ej for second-person singular, -te/-ete/-ejte for second-person plural and -me/-eme/-ejme for first-person plural. The conditional mood is formed with a particle after the past-tense verb. This mood indicates possible events, expressed in English as "I would" or "I wish".
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Answer: verb

Extract the answer to the question from the following context. Question: What did a waiter do for people? Context: A reconciliation of these views is suggested by William Atwood: "Undoubtedly [Chopin's] use of traditional musical forms like the polonaise and mazurka roused nationalistic sentiments and a sense of cohesiveness amongst those Poles scattered across Europe and the New World ... While some sought solace in [them], others found them a source of strength in their continuing struggle for freedom. Although Chopin's music undoubtedly came to him intuitively rather than through any conscious patriotic design, it served all the same to symbolize the will of the Polish people ..."
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Answer:
served