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.

Q: Context: During active transport, molecules move from an area of low concentration to an area of high concentration. This is the opposite of diffusion, and these molecules are said to flow against their concentration gradient. Active transport is called "active" because this type of transport requires energy to move molecules. ATP is the most common source of energy for active transport. As molecules are moving against their concentration gradients, active transport cannot occur without assistance. A carrier protein is always required in this process. Like facilitated diffusion, a protein in the membrane carries the molecules across the membrane, except this protein moves the molecules from a low concentration to a high concentration. These proteins are often called "pumps" because they use energy to pump the molecules across the membrane. There are many cells in your body that use pumps to move molecules. For example, your nerve cells (neurons) would not send messages to your brain unless you had protein pumps moving molecules by active transport. The sodium-potassium pump ( Figure 1.1) is an example of an active transport pump. The sodium-potassium pump uses ATP to move three sodium (Na+ ) ions and two potassium (K+ ) ions to where they are already highly concentrated. Sodium ions move out of the cell, and potassium ions move into the cell. How do these ions then return to their original positions? As the ions now can flow down their concentration gradients, facilitated diffusion returns the ions to their original positions either inside or outside the cell. 
 Question: which statement is true concerning active transport?

A: during active transport, molecules move from an area of low concentration to
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Q: Context: September 1939. Mrs. Kay Miniver (Greer Garson) and her family live a comfortable life at a house called 'Starlings' in Belham, a fictional village outside London, England. The house has a large garden, with a private landing stage on the River Thames at which is moored a motorboat belonging to her devoted husband Clem (Walter Pidgeon), a successful architect. They have three children: the youngsters Toby and Judy (Christopher Severn and Clare Sandars) and an older son Vin (Richard Ney) at university. They have live-in staff: Gladys the housemaid (Brenda Forbes) and Ada the cook (Marie De Becker).As World War II looms, Vin comes down from university and meets Carol Beldon (Teresa Wright), granddaughter of Lady Beldon (Dame May Whitty) from nearby Beldon Hall. Despite initial disagreements (mainly contrasting Vin's idealistic attitude to class differences with Carol's practical altruism) they fall in love. Vin proposes to Carol in front of his family at home after his younger brother prods him to give a less romantic but more honest proposal.Several months later, as the war comes closer to home with the bombing of Great Brittan, Vin feels he must "do his bit" and enlists in the Royal Air Force, qualifying as a fighter pilot. He is posted to a base near to his parents' home and is able to signal his safe return from operations to his parents by cutting his engines briefly as he flies over the house. Together with other boat owners, Clem volunteers to take his motorboat to assist in the May-June 1940 Dunkirk evacuation.Early one morning, Kay unable to sleep as Clem is still away, wanders down to the landing stage. She is startled to discover a wounded German pilot (Helmut Dantine) hiding in her garden and he holds her at gunpoint. Demanding food and a coat, the pilot maniacally asserts that the Third Reich will mercilessly overcome its enemies. She feeds him, calmly disarms him and then calls the police. Soon after, Clem returns home, exhausted, from Dunkirk.Lady Beldon visits Kay to try and convince her to talk Vin out of marrying Carol on account of her granddaughter's comparative youth. Lady Beldon is unsuccessful and admits defeat when Kay reminds her that she, too, was young when she married her late husband. Lady Beldon concedes defeat and realises that she would be foolish to try and stop the marriage. Vin and Carol are married; Carol has now also become Mrs Miniver, and they return from their honeymoon in Scotland. A key theme is that she knows he is likely to be killed in action, but the short love will fill her life. Later, Kay and her family take refuge in their Anderson shelter in the garden during an air raid, and attempt to keep their minds off the frightening bombing by reading Alice's Adventures in Wonderland, which Clem refers to as a "lovely story" as they barely survive a bomb destroys parts of the house. They take the damage with nonchalance.At the annual village flower show, Lady Beldon silently disregards the judges' decision that her rose is the winner, instead announcing the entry of the local stationmaster, Mr. Ballard (Henry Travers), named the "Mrs. Miniver" rose, as the winner, with her own rose taking second prize. As air raid sirens sound and the villagers take refuge in the cellars of Beldon Hall, Kay and Carol drive Vin to join his squadron. On their journey home they witness fighter planes in a 'dogfight'. For safety, Kay stops the car and they see the German plane crash. Kay realises Carol has been wounded by shots from the plane and takes her back to 'Starlings'. She dies a few minutes after they reach home. Kay is devastated. When Vin returns from battle, he already knows the terrible news. Unexpectedly he is the survivor, and she the one who gives her life for England.The villagers assemble at the badly damaged church where their vicar (Henry Wilcoxon) affirms their determination in a powerful sermon:"We in this quiet corner of England have suffered the loss of friends very dear to us, some 
 Question: Who enlists in the Royal Air Force?

A: vin
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Q: Context: While the United States continued missions to the Moon in the early 1970s, the Soviets worked to build a space station. A space station is a large spacecraft. People can live on this craft for a long period of time. Between 1971 and 1982, the Soviets put a total of seven Salyut space stations into orbit. Figure 23.22 shows the last of these, Salyut 7. These were all temporary stations. They were launched and later inhabited by a human crew. Three of the Salyut stations were used for secret military purposes. The others were used to study the problems of living in space. Cosmonauts aboard the stations performed a variety of experiments in astronomy, biology, and Earth science. Salyut 6 and Salyut 7 each had two docking ports. One crew could dock a spacecraft to one end. A replacement crew could dock to the other end. The U.S. only launched one space station during this time. It was called Skylab. Skylab was launched in May 1973. Three crews visited Skylab, all within its first year in orbit. Skylab was used to study the effects of staying in space for long period. Devices on board were and for studying the Sun. Skylab reentered Earths atmosphere in 1979, sooner than expected. The first space station designed for long-term use was the Mir space station (Figure 23.23). Mir was launched in several separate pieces. These pieces were put together in space. Mir holds the current record for the longest continued presence in space. There were people living on Mir continuously for almost 10 years! Mir was the first major space project in which the United States and Russia worked together. American space shuttles transported supplies and people to and from Mir. American astronauts lived on Mir for many months. This cooperation allowed the two nations to learn from each other. The U.S. learned about Russias experiences with long-duration space flights. Mir was taken out of orbit in 2001. It fell into the Pacific Ocean. The International Space Station, shown in Figure 23.24 is a joint project between the space agencies of many nations These include the United States (NASA), Russia (RKA), Japan (JAXA), Canada (CSA), several European countries (ESA) and the Brazilian Space Agency. The International Space Station is a very large station. It has many different sections and is still being assembled. The station has had people on board since 2000. American space shuttles deliver most of the supplies and equipment to the station. Russian Soyuz spacecraft carry people. The primary purpose of the station is scientific research. This is important because the station has a microgravity environment. Experiments are done in the fields of biology, chemistry, physics, physiology and medicine. NASA wanted a new kind of space vehicle. This vehicle had to be reusable. It had to able to carry large pieces of equipment, such as satellites, space telescopes, or sections of a space station. The new vehicle was called a space shuttle, shown in Figure 23.25. There have been five space shuttles: Columbia, Challenger, Discovery, Atlantis, and Endeavor. A space shuttle has three main parts. You are probably most familiar with the orbiter. This part has wings like At the end of the mission, the orbiter re-enters Earths atmosphere. The outside heats up as it descends. Pilots have to steer the shuttle to the runway very precisely. Space shuttles usually land at Kennedy Space Center or at Edwards Air Force Base in California. The orbiter is later hauled back to Florida on the back of a jet airplane. The space shuttle program has been very successful. Over 100 mission have been flown. Space shuttle missions have made many scientific discoveries. Crews have launched many satellites. There have been other great achievements in space. However, the program has also had two tragic disasters. The first came just 73 seconds after launch, on January 28, 1986. The space shuttle Challenger disintegrated in mid-air, as shown in Figure 23.27. On board were seven crew members. All of them died. One of them was Christa McAuliffe, who was to be the first teacher in space. 
 Question: space station with the longest continuous use

A:
mir
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