Problem: Predation:

Predators may increase the biodiversity of communities by preventing a single species from becoming dominant. Such predators are known as keystone species and may have a profound influence on the balance of organisms in a particular ecosystem. Introduction or removal of this predator, or changes in its population density, can have drastic cascading effects on the equilibrium of many other populations in the ecosystem. For example, grazers of a grassland may prevent a single dominant species from taking over.

What is increased by keeping a single species from being dominant in an ecosystem?
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A: biodiversity of communities

Problem: Boston has a strong mayor council government system in which the mayor (elected every fourth year) has extensive executive power. Marty Walsh became Mayor in January 2014, his predecessor Thomas Menino's twenty-year tenure having been the longest in the city's history. The Boston City Council is elected every two years; there are nine district seats, and four citywide "at-large" seats. The School Committee, which oversees the Boston Public Schools, is appointed by the mayor.
What kind of power does the mayor have?
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Answer: extensive executive power

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
More recently, films such as Das Boot (1981), The Never Ending Story (1984) Run Lola Run (1998), Das Experiment (2001), Good Bye Lenin! (2003), Gegen die Wand (Head-on) (2004) and Der Untergang (Downfall) (2004) have enjoyed international success. In 2002 the Academy Award for Best Foreign Language Film went to Caroline Link's Nowhere in Africa, in 2007 to Florian Henckel von Donnersmarck's The Lives of Others. The Berlin International Film Festival, held yearly since 1951, is one of the world's foremost film and cinema festivals.
What award did Nowhere in Africa win in 2002?
A: Academy Award for Best Foreign Language Film

Context and question: The major landmark of puberty for males is the first ejaculation, which occurs, on average, at age 13. For females, it is menarche, the onset of menstruation, which occurs, on average, between ages 12 and 13. The age of menarche is influenced by heredity, but a girl's diet and lifestyle contribute as well. Regardless of genes, a girl must have a certain proportion of body fat to attain menarche. Consequently, girls who have a high-fat diet and who are not physically active begin menstruating earlier, on average, than girls whose diet contains less fat and whose activities involve fat reducing exercise (e.g. ballet and gymnastics). Girls who experience malnutrition or are in societies in which children are expected to perform physical labor also begin menstruating at later ages.
What is a female's major landmark of puberty?
Answer: menstruation

Question: Most copper is mined or extracted as copper sulfides from large open pit mines in porphyry copper deposits that contain 0.4 to 1.0% copper. Examples include Chuquicamata in Chile, Bingham Canyon Mine in Utah, United States and El Chino Mine in New Mexico, United States. According to the British Geological Survey, in 2005, Chile was the top mine producer of copper with at least one-third world share followed by the United States, Indonesia and Peru. Copper can also be recovered through the in-situ leach process. Several sites in the state of Arizona are considered prime candidates for this method. The amount of copper in use is increasing and the quantity available is barely sufficient to allow all countries to reach developed world levels of usage.
Is there an answer to this question: What is the name of the process being considered in Arizona that allows copper to be recovered?

Answer: in-situ leach process

Question: In the early 15th century, the countries of the Iberian peninsula began to sponsor exploration beyond the boundaries of Europe. Prince Henry the Navigator of Portugal (d. 1460) sent expeditions that discovered the Canary Islands, the Azores, and Cape Verde during his lifetime. After his death, exploration continued; Bartolomeu Dias (d. 1500) went around the Cape of Good Hope in 1486 and Vasco da Gama (d. 1524) sailed around Africa to India in 1498. The combined Spanish monarchies of Castile and Aragon sponsored the voyage of exploration by Christopher Columbus (d. 1506) in 1492 that discovered the Americas. The English crown under Henry VII sponsored the voyage of John Cabot (d. 1498) in 1497, which landed on Cape Breton Island.
Is there an answer to this question: What did Christopher Columbus discover in 1492?

Answer:
the Americas