instruction:
In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.
question:
Passage: On 21 January 1818, Friedrich married Caroline Bommer, the twenty-five-year-old daughter of a dyer from Dresden. The couple had three children, with their first, Emma, arriving in 1820.  Physiologist and painter Carl Gustav Carus notes in his biographical essays that marriage did not impact significantly on either Friedrich's life or personality, yet his canvasses from this period, including Chalk Cliffs on Rügen—painted after his honeymoon—display a new sense of levity, while his palette is brighter and less austere. Human figures appear with increasing frequency in the paintings of this period, which Siegel interprets as a reflection that "the importance of human life, particularly his family, now occupies his thoughts more and more, and his friends, his wife, and his townspeople appear as frequent subjects in his art."Around this time, he found support from two sources in Russia. In 1820, the Grand Duke Nikolai Pavlovich, at the behest of his wife Alexandra Feodorovna, visited Friedrich's studio and returned to Saint Petersburg with a number of his paintings, an exchange that began a patronage that continued for many years. Not long thereafter, the poet Vasily Zhukovsky, tutor to Alexander II, met Friedrich in 1821 and found in him a kindred spirit. For decades Zhukovsky helped Friedrich both by purchasing his work himself and by recommending his art to the royal family; his assistance toward the end of Friedrich's career proved invaluable to the ailing and impoverished artist. Zhukovsky remarked that his friend's paintings "please us by their precision, each of them awakening a memory in our mind."Friedrich was acquainted with Philipp Otto Runge, another leading German painter of the Romantic period. He was also a friend of Georg Friedrich Kersting, and painted him at work in his unadorned studio, and of the Norwegian painter Johan Christian Clausen Dahl (1788–1857). Dahl was close to Friedrich during the artist's final years, and he expressed dismay that to the art-buying public, Friedrich's pictures were only "curiosities". While the poet Zhukovsky appreciated Friedrich's psychological themes, Dahl praised the descriptive quality of Friedrich's landscapes, commenting that "artists and connoisseurs saw in Friedrich's art only a kind of mystic, because they themselves were only looking out for the mystic... They did not see Friedrich's faithful and conscientious study of nature in everything he represented".During this period Friedrich frequently sketched memorial monuments and sculptures for mausoleums, reflecting his obsession with death and the afterlife; he even created designs for some of the funerary art in Dresden's cemeteries. Some of these works were lost in the fire that destroyed Munich's Glass Palace (1931) and later in the 1945 bombing of Dresden.
answer:
What is the full name of the person whose assistance toward the end of Friedrich's career proved invaluable to the ailing and impoverished artist?


question:
Passage: The first eruptions of Nevado del Ruiz occurred about 1.8 million years ago at the beginning of the Pleistocene epoch. Three primary eruption periods in the history of the massif have been identified: ancestral, older and present. During the ancestral period between one million to two million years ago, a complex of large stratovolcanoes was created. Between 1.0 million and 0.8 million years ago, they partially collapsed, forming large (5–10 km wide) calderas. During the older period, which lasted from 0.8 million to 0.2 million years ago, a new complex of large stratovolcanoes developed (including Older Ruiz, Tolima, Quindio, and Santa Isabel). Once again explosive summit calderas formed from 0.2 million to 0.15 million years ago.The present period began about 150,000 years ago and involved the development of the present volcanic edifice through the emplacement of lava domes made of andesite and dacite (igneous rocks) inside older calderas. During the past 11,000 years, Nevado del Ruiz passed through at least 12 eruption stages, which included multiple slope failures (rock avalanches), pyroclastic flows and lahars leading to partial destruction of the summit domes. During the past several thousand years, eruptions of the volcanoes in the Ruiz–Tolima massif have mostly been small, and the pyroclastic flow deposits have been much less voluminous than during the Pleistocene. Since the volcano's earlier eruptions are not recorded, volcanologists have used tephrochronology to date them.During recorded history, eruptions have consisted primarily of a central vent eruption (in the caldera) followed by an explosive eruption, then lahars. Ruiz's earliest identified Holocene eruption was about 6660 BC, and further eruptions occurred in 1245 BC ± 150 years (dated through radiocarbon dating), about 850 BC, 200 BC ± 100 years, 350 AD ± 300 years, 675 AD ± 50 years, in 1350, 1541 (perhaps), 1570, 1595, 1623, 1805, 1826, 1828 (perhaps),[b] 1829, 1831, 1833 (perhaps),[b] 1845, 1916, December 1984 – March 1985, September 1985 – July 1991, and possibly in April 1994.[b] Many of these eruptions involved a central vent eruption, a flank vent eruption, and a phreatic (steam) explosion. Ruiz is the second-most active volcano in Colombia after Galeras.
answer:
What partially collapsed, forming large (5–10 km wide) calderas?


question:
Passage: Like all creeks in Lycoming County, Larrys Creek served as an area for settlers to establish homesteads and farms. As logging became a major industry in the mid-19th century, the creek was a source of power for sawmills and other mills. The first sawmill on the creek, in what is now Mifflin Township, was built in 1799. The relatively low flow of water in the creek did not allow rafts of logs to be floated downstream to the river and the lumber boom at Williamsport (as they were on Pine Creek to the west).This and the lack of logging railroads along the creek led to the development of many small sawmills: the Larrys Creek watershed once had 53 sawmills within 22 miles (35 km) of the mouth (as well as other industries of the time). No other stream in the country had so many sawmills in so small a territory. Twelve sawmills were on the Second Fork, six on the First Fork, one each on Canoe Run and Lawshe Run, and the rest were on Larrys Creek itself. Eight were structures rebuilt on the site of previous sawmills, and only four were steam powered (the rest were water powered). The earliest of these sawmills was built in 1796 (near Seeley Run), the last in 1902 (on Lawshe Run), and by 1903 just two mills were still standing and only one of those was operating.Lumbering removed the tree trunks, but left many flammable limbs, branches, and stumps behind. On May 2, 1872, a large forest fire destroyed the villages of Carter and Gould, 6 miles (9.7 km) north of Salladasburg on Larrys Creek in Mifflin Township. There are large tracts of second growth forest and small lumber companies still operate in the watershed today.
answer:

What were the names of the streams where the sawmills were located?