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.

Context: Something in chocolate could be used to stop coughs and lead to more effective medicines, say UK researchers. Their study found that theobromine , found in cocoa, was nearly a third more effective in stopping coughs than codeine, which was considered the best cough medicine at present. The Imperial College London researchers who published their results online said the discovery could lead to more effective cough treatment. "While coughing is not necessarily harmful it can have a major effect on the quality of life, and this discovery could be a huge step forward in treating this problem," said Professor Peter Barnes. Ten healthy volunteers were given theobromine, codeine or placebo, a pill that contains no medicine, during the experiment. Neither the volunteers nor the researchers knew who received which pill. The researchers then measured levels of capsaicin, which is used in research to cause coughing and as a sign of how well the medicines are stopping coughs. The team found that, when the volunteers were given theobromine, the capsaicin needed to produce a cough was around a third higher than in the placebo group. When they were given codeine they needed only slightly higher levers of capsaicin to cause a cough compared with the placebo. The researchers said that theobromine worked by keeping down a nerve activity , which cause coughing. They also found that unlike some standard cough treatments, theobromine caused no side effects such as sleepiness. 
 Question: What was used in the experiment to cause coughing?
capsaicin.

Context: The movie opens with Ralph Wiggum singing along to the 20th Century Fox logo. We then cut to Itchy & Scratchy: The Movie. They are out on the moon. Itchy kills Scratchy and then returns to earth and is painted as a hero by the media. Shortly thereafter, Itchy is elected president. Later as Itchy is in the White House, he sees a supposedly dead Scratchy on the moon. Scratchy holds up a sign that says "I'm telling", which freaks President Itchy out. Itchy then retaliates by sending a hundred missiles toward Scratchy. This is then seen in the theater which is being attended by the Simpsons. Homer stands up and yells "Boring!". Lisa replies "Dad, we can't see the movie!". Homer then goes off on a tirade about why they're paying to watch something in the theater that they normally watch on TV, and that everyone in the audience is a gigantic sucker, especially you. Cue a very fancy and stylized version of the standard Simpsons opening theme.The opening ends with Green Day hosting a concert at Lake Springfield (Singing the Simpsons theme after the opening credits). After they finish their song, they talk about the environment. The audience becomes angry and begins to throw garbage at them polluting the lake and causing their barge to dissolve and sink, killing them. The next day at church, while they have a short memorial for Green Day, Grampa is possessed by God warns the city of a future disaster. Marge believes Grampa's prediction, and decides to work out the meaning of the message. Meanwhile, Lisa starts to talk about the environment, with no success. She encounters Colin, an Irish boy who shares the same passions as her. Homer gets a note from Marge of his chores, and one is fixing the sinkhole. Instead of fixing it, Homer puts Maggie's sandbox over it. His next chore is to fix the roof. While repairing the roof, Homer and Bart decide to have a dare contest. Homer dares Bart to climb the antenna. Bart does so, and gets stuck. Homer shakes it in order to get Bart down. Homer dares Bart to skateboard to Krusty Burger naked, which Bart object's to, saying girls will see his "doodle". After Homer threatens to call him chicken for the rest of his life, Bart agrees. Bart becomes stuck naked on the window of the building. After he is apprehended by the police, and tied to a Stop sign pole, Homer turns up and they decide to order a meal, he brings him socks and a shirt, and no pants. Inside the restuarant, Ned Flanders helps Bart out by giving him a pair of pants, and understands his feelings which begins a relationship and mutual respect between the two. Meanwhile Krusty is filming a commercial. When recording finishes Krusty orders for the pig he is using in the commercial to be slaughtered, causing it to flee to Homer who adopts him, and calls him Spider-Pig. That evening Lisa holds a conference at city hall, called "An Irritating Truth" and explains that the town lake cannot sustain anymore pollution. Mayor Quimby declares a state of emergency and orders the cleansing and protection of Lake Springfield.They put up a fence around the lake to halt further dumping, and announce it is idiot proof, using Cletus as an example to try to throw a possum in the lake, and fail. Soon, Marge asks Homer where "Spider-Pig's/Harry Plopper's" waste is going. Homer shows her an overflowing silo, asking how a pig can fill it up in two days, Homer replies that he helped, horrifying Marge who tells Homer to dispose of it safely. While waiting in a queue at the dump Homer is told by Lenny that Lard Lad Donuts has been shut down and that they are giving away free donuts. Homer, in his haste to get to the giveaway decides on a quicker means of disposal and dumps the silo into the lake, causing it to become heavily polluted. A nearby squirrel jumps into it and becomes severely mutated, with many eyes. Nearby, 
 Question: What do Lisa and Colin convince the entire town to clean?
the lake

Context: A magnet is an object that attracts certain materials such as iron. Youre probably familiar with common bar magnets, like the one in Figure 24.2. Like all magnets, this bar magnet has north and south poles and attracts objects such as paper clips that contain iron. All magnets have two magnetic poles. The poles are regions where the magnet is strongest. The poles are called north and south because they always line up with Earths north-south axis if the magnet is allowed to move freely. (Earths axis is the imaginary line around which the planet rotates.) What do you suppose would happen if you cut the bar magnet in Figure 24.2 in half along the line between the north and south poles? Both halves would also have north and south poles. If you cut each of the halves in half, all those pieces would have north and south poles as well. Pieces of a magnet always have both north and south poles no matter how many times you cut the magnet. The force that a magnet exerts on certain materials is called magnetic force. Like electric force, magnetic force is exerted over a distance and includes forces of attraction and repulsion. North and south poles of two magnets attract each other, while two north poles or two south poles repel each other. Like the electric field that surrounds a charged particle, a magnetic field surrounds a magnet. This is the area around the magnet where it exerts magnetic force. Figure 24.3 shows the magnetic field surrounding a bar magnet. Tiny bits of iron, called iron filings, were placed under a sheet of glass. When the magnet was placed on the glass, it attracted the iron filings. The pattern of the iron filings shows the lines of force that make up the magnetic field of the magnet. The concentration of iron filings near the poles indicates that these areas exert the strongest force. To see an animated magnetic field of a bar magnet, go to this URL: [Link] When two magnets are brought close together, their magnetic fields interact. You can see how in Figure 24.4. The drawings show how lines of force of north and south poles attract each other whereas those of two north poles repel each other. The animations at the URL below show how magnetic field lines change as two or more magnets move in relation to each other. You can take an animated quiz to check your understanding of magnetic field interactions at this URL: [Link] Magnetism is the ability of a material to be attracted by a magnet and to act as a magnet. No doubt youve handled refrigerator magnets like the ones in Figure 24.5. You probably know first-hand that they stick to a metal refrigerator but not to surfaces such as wooden doors and glass windows. Wood and glass arent attracted to a magnet, whereas the steel refrigerator is. Obviously, only certain materials respond to magnetic force. Magnetism is due to the movement of electrons within atoms of matter. When electrons spin around the nucleus of an atom, it causes the atom to become a tiny magnet, with north and south poles and a magnetic field. In most materials, the electrons orbiting the nuclei of the atoms are arranged in such a way that the materials have no magnetic properties. Also, in most types of matter, the north and south poles of atoms point in all different directions, so overall the matter is not magnetic. Examples of nonmagnetic materials include wood, glass, plastic, paper, copper, and aluminum. These materials are not attracted to magnets and cannot become magnets. In other materials, electrons fill the orbitals of the atoms that make up the material in a way to allow for each atom to have a tiny magnetic field, giving each atom a tiny north and south pole. There are large areas where the north and south poles of atoms are all lined up in the same direction. These areas are called magnetic domains. Generally, the magnetic domains point in different directions, so the material is still not magnetic. However, the material can be magnetized by placing it in a magnetic field. When this happens, all the magnetic domains become aligned, and the material becomes 
 Question: force of attraction or repulsion exerted by a magnet

magnetic force