Problem: Paris in its early history had only the Seine and Bievre rivers for water. From 1809, the Canal de l'Ourcq provided Paris with water from less-polluted rivers to the north-east of the capital. From 1857, the civil engineer Eugene Belgrand, under Napoleon III, oversaw the construction of a series of new aqueducts that brought water from locations all around the city to several reservoirs built atop the Capital's highest points of elevation. From then on, the new reservoir system became Paris' principal source of drinking water, and the remains of the old system, pumped into lower levels of the same reservoirs, were from then on used for the cleaning of Paris' streets. This system is still a major part of Paris' modern water-supply network. Today Paris has more than 2,400 km (1,491 mi) of underground passageways dedicated to the evacuation of Paris' liquid wastes.
Who was Eugene Belgrand under?
The answer is the following: Napoleon III

Problem: The large external sculptural schemes of Early Gothic churches gave way to more sculpture inside the building, as tombs became more elaborate and other features such as pulpits were sometimes lavishly carved, as in the Pulpit by Giovanni Pisano in Sant'Andrea. Painted or carved wooden relief altarpieces became common, especially as churches created many side-chapels. Early Netherlandish painting by artists such as Jan van Eyck (d. 1441) and Rogier van der Weyden (d. 1464) rivalled that of Italy, as did northern illuminated manuscripts, which in the 15th century began to be collected on a large scale by secular elites, who also commissioned secular books, especially histories. From about 1450 printed books rapidly became popular, though still expensive. There were around 30,000 different editions of incunabula, or works printed before 1500, by which time illuminated manuscripts were commissioned only by royalty and a few others. Very small woodcuts, nearly all religious, were affordable even by peasants in parts of Northern Europe from the middle of the 15th century. More expensive engravings supplied a wealthier market with a variety of images.
Along with being carved, how were altarpieces often decorated in this period?
The answer is the following: Painted

Problem: Jehovah's Witnesses are perhaps best known for their efforts to spread their beliefs, most notably by visiting people from house to house, distributing literature published by the Watch Tower Society in 700 languages. The objective is to start a regular "Bible study" with any person who is not already a member, with the intention that the student be baptized as a member of the group; Witnesses are advised to consider discontinuing Bible studies with students who show no interest in becoming members. Witnesses are taught they are under a biblical command to engage in public preaching. They are instructed to devote as much time as possible to their ministry and are required to submit an individual monthly "Field Service Report". Baptized members who fail to report a month of preaching are termed "irregular" and may be counseled by elders; those who do not submit reports for six consecutive months are termed "inactive".
What are Jehovah Witnesses probably best known for by outsiders?
The answer is the following: their efforts to spread their beliefs

Problem: The United States launched the orbital workstation Skylab 1 on May 14, 1973. It weighed 169,950 pounds (77,090 kg), was 58 feet (18 m) long by 21.7 feet (6.6 m) in diameter, with a habitable volume of 10,000 cubic feet (280 m3). Skylab was damaged during the ascent to orbit, losing one of its solar panels and a meteoroid thermal shield. Subsequent manned missions repaired the station, and the final mission's crew, Skylab 4, set the Space Race endurance record with 84 days in orbit when the mission ended on February 8, 1974. Skylab stayed in orbit another five years before reentering the Earth's atmosphere over the Indian Ocean and Western Australia on July 11, 1979.
How much did the Skylab 1 weigh?
The answer is the following:
169,950 pounds