instruction:
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.
question:
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?
answer:
capsaicin.


question:
Context: Sir Balan le Savage, brother of Sir Balin from Northumberland, is a minor character mentioned in various Arthurian legends. 
 Question: Who was the brother of Sir Balan?
answer:
sir balin


question:
Context: Ice is an example of solid matter. A solid is matter that has a fixed volume and a fixed shape. Figure 4.3 shows examples of matter that are usually solids under Earth conditions. In the figure, salt and cellulose are examples of crystalline solids. The particles of crystalline solids are arranged in a regular repeating pattern. The steaks and candle wax are examples of amorphous ("shapeless") solids. Their particles have no definite pattern. Ocean water is an example of a liquid. A liquid is matter that has a fixed volume but not a fixed shape. Instead, a liquid takes the shape of its container. If the volume of a liquid is less than the volume of its container, the top surface will be exposed to the air, like the oil in the bottles in Figure 4.4. Two interesting properties of liquids are surface tension and viscosity. Surface tension is a force that pulls particles at the exposed surface of a liquid toward other liquid particles. Surface tension explains why water forms droplets, like those in Figure 4.5. Viscosity is a liquids resistance to flowing. Thicker liquids are more viscous than thinner liquids. For example, the honey in Figure 4.5 is more viscous than the vinegar. You can learn more about surface tension and viscosity at these URLs: [Link] [Link] (1:40) MEDIA Click image to the left or use the URL below. URL: Water vapor is an example of a gas. A gas is matter that has neither a fixed volume nor a fixed shape. Instead, a gas takes both the volume and the shape of its container. It spreads out to take up all available space. You can see an example in Figure 4.6. Youre probably less familiar with plasmas than with solids, liquids, and gases. Yet, most of the universe consists of plasma. Plasma is a state of matter that resembles a gas but has certain properties that a gas does not have. Like a gas, plasma lacks a fixed volume and shape. Unlike a gas, plasma can conduct electricity and respond to magnetism. Thats because plasma contains charged particles called ions. This gives plasma other interesting properties. For example, it glows with light. Where can you find plasmas? Two examples are shown in Figure 4.7. The sun and other stars consist of plasma. Plasmas are also found naturally in lightning and the polar auroras (northern and southern lights). Artificial plasmas are found in fluorescent lights, plasma TV screens, and plasma balls like the one that opened this chapter. You can learn more about plasmas at this URL: (2:58). MEDIA Click image to the left or use the URL below. URL: Why do different states of matter have different properties? Its because of differences in energy at the level of atoms and molecules, the tiny particles that make up matter. Energy is defined as the ability to cause changes in matter. You can change energy from one form to another when you lift your arm or take a step. In each case, energy is used to move matter you. The energy of moving matter is called kinetic energy. The particles that make up matter are also constantly moving. They have kinetic energy. The theory that all matter consists of constantly moving particles is called the kinetic theory of matter. You can learn more about it at the URL below. Particles of matter of the same substance, such as the same element, are attracted to one another. The force of attraction tends to pull the particles closer together. The particles need a lot of kinetic energy to overcome the force of attraction and move apart. Its like a tug of war between opposing forces. The kinetic energy of individual particles is on one side, and the force of attraction between different particles is on the other side. The outcome of the "war" depends on the state of matter. This is illustrated in Figure 4.8 and in the animation at this URL: [Link] In solids, particles dont have enough kinetic energy to overcome the force of attraction between them. The particles are packed closely together and cannot move around. All they can do 
 Question: Which state of matter has particles with the least energy?
answer:

solid