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.
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Question: Passage: The two main requirements of an anti-torque system are that it should prevent rotation of the sonde, and it should allow easy movement of the drill up and down the borehole. Attempts have been made to design drills with counter-rotating components so that overall torque is minimized, but these have had limited success. Five kinds of anti-torque systems have been devised for use with cable-suspended EM drills, though not all are in current use, and some drills have used a combination of more than one design. The first drill to require an anti-torque system was used at Camp Century by CRREL in 1966; the drill incorporated a set of hinged friction blades that swung out from the sonde when the drill motor was started. These were found to have very weak friction against the borehole wall, and were ineffective; the drill had to be controlled carefully to prevent twisting the cable. No other drills have attempted to use this approach.For the next deployment of the drill leaf springs were installed, and this has proved to be a more durable design. These are mounted vertically, with a curve outwards so that they are easily compressed by the borehole wall, and can slide up and down with the movement of the drill. They pass easily through any areas of irregularity in the borehole, but the edges of the springs cut into the borehole wall and prevent rotation. Leaf springs are very simple mechanically, with the additional benefit of being easy to adjust by changing the spacing between the end points. They can be placed anywhere on the drill that does not rotate, so they do not add length to the sonde. The shape is usually a fourth-order parabola, since this has been determined to provide the most even loading against the borehole wall. Leaf springs have been found to be so effective that they can prevent rotation even in heavy drills running at full power.Skate antitorque systems have blades attached to vertical bars which are pushed against the borehole wall; the blades dig into the wall and provide the anti-torque. Skates can be built with springs which allow them to keep the blades pressed against the wall in an irregular borehole, and to prevent problems in narrower parts of the borehole. Although skates are a popular design for anti-torque and have been used with success, they have difficulty preventing rotation in firn and at boundaries between layers of different densities, and can cause problems when drilling with high torque. When they fail, they act as reamers, removing chips from the wall which can fall to the drillbit and interfere with drilling.

Answer: What acts as reamers when they fail?

Question: Passage: Michael Joseph Jackson (August 29, 1958 June 25, 2009) was an American singer, songwriter, and dancer. Dubbed the "King of Pop", he is widely regarded as one of the most significant cultural figures of the 20th century and one of the greatest entertainers of all time. He was also known for his unorthodox lifestyle, residing in a private amusement park he called Neverland Ranch, and often becoming the focus of tabloid scrutiny. Jackson's contributions to music, dance, and fashion, along with his publicized personal life, made him a global figure in popular culture for over four decades.
The eighth child of the Jackson family, Michael made his professional debut in 1964 with his elder brothers Jackie, Tito, Jermaine, and Marlon as a member of the Jackson 5. He began his solo career in 1971 while at Motown Records, and in the early 1980s, became a dominant figure in popular music. His music videos, including those for "Beat It", "Billie Jean", and "Thriller" from his 1982 album Thriller, are credited with breaking racial barriers and transforming the medium into an art form and promotional tool. Their popularity helped bring the television channel MTV to fame. Bad (1987) was the first album to produce five US Billboard Hot 100 number-one singles. He continued to innovate throughout the 1990s with videos such as "Black or White" and "Scream", and forged a reputation as a touring artist. Through stage and video performances, Jackson popularized complicated dance techniques such as the robot and the moonwalk, to which he gave the name. His sound and style have influenced artists of various genres.
Jackson is one of the best-selling music artists of all time, with estimated sales of over 350 million records worldwide; Thriller is the best-selling album of all time, with estimated sales of 66 million copies worldwide. His other albums, including Off the Wall (1979), Bad (1987), Dangerous (1991), and HIStory (1995), also rank among the world's best-selling. He won hundreds of awards (more than any other artist in the history of popular music), has been inducted into the Rock and Roll Hall of Fame twice, and is the only pop or rock artist to have been inducted into the Dance Hall of Fame. His other achievements include Guinness world records (including the Most Successful Entertainer of All Time), 15 Grammy Awards (including the Legend and Lifetime Achievement awards), 26 American Music Awards (more than any other artist), and 13 number-one US singles (more than any other male artist in the Hot 100 era). Jackson was the first artist to have a top ten single in the Billboard Hot 100 in five different decades. In 2016, his estate earned $825 million, the highest yearly amount for a celebrity ever recorded by Forbes.

Answer: What is the first name of the person whose estate in 2016, earned $825 million, the highest yearly amount for a celebrity ever recorded by Forbes?

Question: Passage: At a St. Louis opera house in 1860, a singer in blackface named Jerry Barton, known as "King of the Minstrels", comes backstage and asks his sweetheart, Lettie Morgan, to elope. Lettie's Aunt Hortense, fearing that Barton is a fortune hunter, tells Lettie she is not the heiress she thought she was and that she has been living off her aunt's charity. With no fortune to hunt, Barton informs Lettie that an artist cannot be burdened with the responsibility of a wife.
Outside the opera house, Lettie meets a chorus girl named Honey, who is preparing to leave with her theatrical troupe in a caravan heading West. When the troupe's producer mistakes Lettie for the star, she joins the group as "Mary Varden". The troupe's wagon train is escorted by Captain Tex Autry of the U.S. Cavalry and his singing plainsmen. The troupe misses the wagon train, however, and must travel alone.
On their way to San Francisco, the caravan is ambushed by a gang of thieves. Tex and his men arrive on the scene and following a gunfight, the gang is chased off. After Tex saves Lettie from a runaway wagon, he comments on the foolishness of risking his men's lives for a bunch of "crazy showgirls". Angered by his insolence, Lettie decides to walk rather than ride with Tex. Eventually she gets tired and asks Tex if she can ride with him. The troupe arrives safely at Fort Henry, which is run by Colonel Seward.

Answer:
What is the first name of the person who is mistaken as Mary Varden?