Problem: Beer is composed mostly of water. Regions have water with different mineral components; as a result, different regions were originally better suited to making certain types of beer, thus giving them a regional character. For example, Dublin has hard water well-suited to making stout, such as Guinness; while the Plzen Region has soft water well-suited to making Pilsner (pale lager), such as Pilsner Urquell. The waters of Burton in England contain gypsum, which benefits making pale ale to such a degree that brewers of pale ales will add gypsum to the local water in a process known as Burtonisation.
What is the main ingredient in beer?
The answer is the following: water

Problem: The American studies program reflected the worldwide anti-Communist ideological struggle. Norman Holmes Pearson, who worked for the Office of Strategic Studies in London during World War II, returned to Yale and headed the new American studies program, in which scholarship quickly became an instrument of promoting liberty. Popular among undergraduates, the program sought to instruct them in the fundamentals of American civilization and thereby instill a sense of nationalism and national purpose. Also during the 1940s and 1950s, Wyoming millionaire William Robertson Coe made large contributions to the American studies programs at Yale University and at the University of Wyoming. Coe was concerned to celebrate the 'values' of the Western United States in order to meet the "threat of communism."
What did the American studies program hope to instruct?
The answer is the following: fundamentals of American civilization

Problem: Many of the limitations of the classic commutator DC motor are due to the need for brushes to press against the commutator. This creates friction. Sparks are created by the brushes making and breaking circuits through the rotor coils as the brushes cross the insulating gaps between commutator sections. Depending on the commutator design, this may include the brushes shorting together adjacent sections and hence coil ends momentarily while crossing the gaps. Furthermore, the inductance of the rotor coils causes the voltage across each to rise when its circuit is opened, increasing the sparking of the brushes. This sparking limits the maximum speed of the machine, as too-rapid sparking will overheat, erode, or even melt the commutator. The current density per unit area of the brushes, in combination with their resistivity, limits the output of the motor. The making and breaking of electric contact also generates electrical noise; sparking generates RFI. Brushes eventually wear out and require replacement, and the commutator itself is subject to wear and maintenance (on larger motors) or replacement (on small motors). The commutator assembly on a large motor is a costly element, requiring precision assembly of many parts. On small motors, the commutator is usually permanently integrated into the rotor, so replacing it usually requires replacing the whole rotor.
What does sparking limit?
The answer is the following: maximum speed

Problem: A few years after its foundation, Montevideo became the main city of the region north of the Rio de la Plata and east of the Uruguay River, competing with Buenos Aires for dominance in maritime commerce. The importance of Montevideo as the main port of the Viceroyalty of the Rio de la Plata brought it in confrontations with the city of Buenos Aires in various occasions, including several times when it was taken over to be used as a base to defend the eastern province of the Viceroyalty from Portuguese incursions.
What were Buenos Aires and Montevideo fighting for dominance over?
The answer is the following:
maritime commerce