instruction:
This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
question:
Passage: Mach argued that, in effect, the water experiment in an otherwise empty universe would remain flat. But if another object were introduced into this universe, perhaps a distant star, there would now be something relative to which the bucket could be seen as rotating. The water inside the bucket could possibly have a slight curve. To account for the curve that we observe, an increase in the number of objects in the universe also increases the curvature in the water. Mach argued that the momentum of an object, whether angular or linear, exists as a result of the sum of the effects of other objects in the universe (Mach's Principle). Question: Mach argued that the momentum of an object exists as a result of the sum of the effects of what?
answer:
effects of other objects in the universe

question:
Passage: The strategy behind the formation of the Warsaw Pact was driven by the desire of the Soviet Union to dominate Central and Eastern Europe. This policy was driven by ideological and geostrategic reasons. Ideologically, the Soviet Union arrogated the right to define socialism and communism and act as the leader of the global socialist movement. A corollary to this idea was the necessity of intervention if a country appeared to be violating core socialist ideas and Communist Party functions, which was explicitly stated in the Brezhnev Doctrine. Geostrategic principles also drove the Soviet Union to prevent invasion of its territory by Western European powers. Question: The Soviet Union feared invasion from which potential enemy?
answer:
Western Europe

question:
Passage: Strasbourg, well known as centre of humanism, has a long history of excellence in higher-education, at the crossroads of French and German intellectual traditions. Although Strasbourg had been annexed by the Kingdom of France in 1683, it still remained connected to the German-speaking intellectual world throughout the 18th century and the university attracted numerous students from the Holy Roman Empire, including Goethe, Metternich and Montgelas, who studied law in Strasbourg, among the most prominent. Nowadays, Strasbourg is known to offer among the best university courses in France, after Paris. Question: What is Strasbourg known as?
answer:
centre of humanism