TASK DEFINITION: Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
PROBLEM: Context: Previous X-ray crystal structures have shown that linkers of five amino acid residues connecting pairs of chicken brain alpha-spectrin and human erythroid beta-spectrin repeats can undergo bending without losing their alpha-helical structure. To test whether bending at one linker can influence bending at an adjacent linker, the structures of two and three repeat fragments of chicken brain alpha-spectrin have been determined by X-ray crystallography. The structure of the three-repeat fragment clearly shows that bending at one linker can occur independently of bending at an adjacent linker. This observation increases the possible trajectories of modeled chains of spectrin repeats. Furthermore, the three-repeat molecule crystallized as an antiparallel dimer with a significantly smaller buried interfacial area than that of alpha-actinin, a spectrin-related molecule, but large enough and of a type indicating biological specificity. Comparison of the structures of the spectrin and alpha-actinin dimers supports weak association of the former, which could not be detected by analytical ultracentrifugation, versus strong association of the latter, which has been observed by others. To correlate features of the structure with solution properties and to test a previous model of stable spectrin and dystrophin repeats, the number of inter-helical interactions in each repeat of several spectrin structures were counted and compared to their thermal stabilities. Inter-helical interactions, but not all interactions, increased in parallel with measured thermal stabilities of each repeat and in agreement with the thermal stabilities of two and three repeats and also partial repeats of spectrin. 
 Question: Alpha-spectrin and beta-spectrin subunits form parallel or antiparallel heterodimers?

SOLUTION: antiparallel

PROBLEM: Context: The Godfather Part II presents two parallel storylines. One involves Mafia chief Michael Corleone in 1958/1959 after the events of the first movie; the other is a series of flashbacks following his father, Vito Corleone from 1917 to 1925, from his youth in Sicily (1901) to the founding of the Corleone family in New York.The film begins in 1901, in the town of Corleone, Sicily, at the funeral of young Vito's father, Antonio Andolini, who has been murdered for an insult to the local Mafia lord, Don Ciccio. During the procession, Vito's older brother is murdered because he swore revenge on the Don. Vito's mother goes to Ciccio to beg for mercy, but he refuses, knowing that nine-year-old Vito will seek revenge later in life. The mother takes Ciccio hostage at knifepoint, allowing her son to escape, and Ciccio's men kill her. They search the town for the boy, but he is aided in his escape by the townspeople. Vito finds his way by ship to New York, and at Ellis Island an immigration agent chooses Vito's hometown of Corleone as his surname, and he is registered as "Vito Corleone".In 1958 in a scene similar to the opening of the first film, Michael Corleone (Al Pacino), Godfather of the Corleone family, deals with various business and family problems during an elaborate party at his Lake Tahoe, Nevada compound to celebrate his son's First Communion. In his office, Michael meets with corrupt Nevada Senator Pat Geary (G. D. Spradlin) to discuss the price of the gaming licenses for the hotel/casinos the Family is buying. Geary, who has obvious contempt for Michael and other Italian businessmen who are moving into his state to take advantage of gambling opportunities, promises to make Michael's acquisition of his gaming license a difficult process. Michael ends his conversation with Geary when he refuses to pay the outrageous fee Geary demands, telling the senator he'll get nothing.Michael also deals with his self-indulgent younger sister Connie (Talia Shire), who, although recently divorced from her second husband, is planning to marry a man named Merl Johnson (Troy Donahue) with no obvious means of support and of whom Michael disapproves. He also talks with Johnny Ola (Dominic Chianese), the right hand man of Jewish gangster Hyman Roth (Lee Strasberg), who is supporting Michael's move into the gambling industry. Belatedly, Michael deals with Frank "Five Angels" Pentangeli (Michael V. Gazzo), a business associate who took over Corleone caporegime Peter Clemenza's territory in New York City after his death, and now has problems with the Rosato Brothers, who are backed by Roth. Pentangeli leaves abruptly, after telling Michael "your father did business with Hyman Roth, your father respected Hyman Roth, but your father never trusted Hyman Roth."Later that night, Michael barely escapes an assassination attempt when his wife Kay (Diane Keaton) notices the bedroom window drapes are inexplicably open, which allows two unseen hitmen to spray the bedroom with bullets. The two hitman are found dead having been killed by a "mole" within the compound. Afterwards, Michael tells his lawyer and associate Tom Hagen (Robert Duvall) that the hit was made with the help of someone close, and that he must leave, entrusting all his power to Hagen to protect his family.Flashback: In 1917 New York City, the adult Vito Corleone (Robert De Niro) works in a grocery store in the Lower East side with his friend Genco Abbandando. The neighborhood is controlled by a member of the "The Black Hand," Don Fanucci (Gastone Moschin), who extorts protection payments from local businesses. One night, Vito's neighbor Clemenza (Bruno Kirby) asks him to hide a stash of guns for him, and later, to repay the favor, takes him to a fancy apartment where they commit their first felony together, stealing an elegant rug.The film flash-forwards to Michael's time. Michael meets with poushal Hyman Roth in Miami, Florida who tells Michael that he believes Frank Pentangeli was responsible for the assassination attempt, and that Pentangeli will pay for it 
 Question: Who visits Sicily for the first time since emigrating?

SOLUTION: vito

PROBLEM: Context: Energy from the Sun comes from the lightest element, hydrogen, fusing together to create the second lightest element, helium. Nuclear fusion on the Sun releases tremendous amounts of solar energy. The energy travels to the Earth, mostly as visible light. The light carries the energy through the empty space between the Sun and the Earth as radiation. Solar energy has been used for power on a small scale for hundreds of years, and plants have used it for billions of years. Unlike energy from fossil fuels, which almost always come from a central power plant or refinery, solar power can be harnessed locally (Figure 1.1). A set of solar panels on a homes rooftop can be used to heat water for a swimming pool or can provide electricity to the house. Societys use of solar power on a larger scale is just starting to increase. Scientists and engineers have very active, ongoing research into new ways to harness energy from the Sun more efficiently. Because of the tremendous amount of incoming sunlight, solar power is being developed in the United States in southeastern California, Nevada, and Arizona. Solar panels supply power to the Interna- tional Space Station. Solar power plants turn sunlight into electricity using a large group of mirrors to focus sunlight on one place, called a receiver (Figure 1.2). A liquid, such as oil or water, flows through this receiver and is heated to a high temperature by the focused sunlight. The heated liquid transfers its heat to a nearby object that is at a lower temperature through a process called conduction. The energy conducted by the heated liquid is used to make electricity. This solar power plant uses mirrors to focus sunlight on the tower in the center. The sunlight heats a liquid inside the tower to a very high temperature, producing energy to make electricity. Solar energy has many benefits. It is extremely abundant, widespread, and will never run out. But there are problems with the widespread use of solar power. Sunlight must be present. Solar power is not useful in locations that are often cloudy or dark. However, storage technology is being developed. The technology needed for solar power is still expensive. An increase in interested customers will provide incentive for companies to research and develop new technologies and to figure out how to mass-produce existing technologies (Figure 1.3). Solar panels require a lot of space. Fortunately, solar panels can be placed on any rooftop to supply at least some of the power required for a home or business. This experimental car is one example of the many uses that engineers have found for solar energy. Click image to the left or use the URL below. URL: Click image to the left or use the URL below. URL: 
 Question: solar energy through the empty space between the sun and earth as ____________.

SOLUTION:
radiation