Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

Input: Consider Input: Restless legs syndrome (RLS), also known as Willis-Ekbom disease, is a sensory-motor neurological disorder with a circadian component. RLS is characterized by uncomfortable sensations in the extremities, generally at night or during sleep, which often leads to an uncontrollable urge to move them for relief. Recently, genomic studies identified single-nucleotide polymorphisms in BTBD9, along with three other genes, as being associated with a higher risk of RLS. Little is known about the function of BTBD9 or its potential role in the pathophysiology of RLS. We therefore examined a line of Btbd9 mutant mice we recently generated for phenotypes similar to symptoms found in RLS patients. We observed that the Btbd9 mutant mice had motor restlessness, sensory alterations likely limited to the rest phase, and decreased sleep and increased wake times during the rest phase. Additionally, the Btbd9 mutant mice had altered serum iron levels and monoamine neurotransmitter systems. Furthermore, the sensory alterations in the Btbd9 mutant mice were relieved using ropinirole, a dopaminergic agonist widely used for RLS treatment. These results, taken together, suggest that the Btbd9 mutant mice model several characteristics similar to RLS and would therefore be the first genotypic mouse model of RLS. Furthermore, our data provide further evidence that BTBD9 is involved in RLS, and future studies of the Btbd9 mutant mice will help shine light on its role in the pathophysiology of RLS. Finally, our data argue for the utility of Btbd9 mutant mice to discover and screen novel therapeutics for RLS.

Output: Willis-Ekbom disease is also known as?


Input: Consider Input: Loma just had to get in touch with someone:"I had to tell my best friend something important. I tried calling her but I couldn't get through. So I sent her an e-mail and then I spoke to her on MSN. Without technology I would not have been able to tell her. " Staying connected with friends and family is important for us. That's why we asked our readers to tell us how cell-phones, e-mail, blogs, text messaging, and personal pages help them keep in touch. More than 1,500 responded. Most of them told us they couldn't live without technology:80%of teens said they need technology to stay in touch. Almost 30%said they'd be completely out of their friends without their cell-phones and other methods of communication. What do they do when they've got news they need to share now? Most teens say they try to reach their friends by phone. But if they don't reach them, they use QQ, e-mails, and text messaging to _ Lots of people use one way of communication--like text messaging--to get a friend's attention and then use another where they can talk more. "My friends and I always tell each other everything that happens. So I send them text messages to tell them to come online so we can talk about it," said Sabeiha. "When planning to get together with friends", Julian said, "the easiest and fastest way I know is to send a text message to my contact group." Jocelyn said. "If I want to go to see a movie with a few friends, I usually send text message to them. By telephone, you have to call every single friend one by one. But text messaging allows you to send the same message to as many as you'd like, which saves a lot of time.

Output: What do most young people use first when they have news to tell their friends?


Input: Consider Input: You dont have to be an ice climber to enjoy ice. Skating and fishing are two other sports that are also done on ice. What is ice? Its simply water in the solid state. The process in which water or any other liquid changes to a solid is called freezing. Freezing occurs when a liquid cools to a point at which its particles no longer have enough energy to overcome the force of attraction between them. Instead, the particles remain in fixed positions, crowded closely together, as shown in the Figure 1.1. The temperature at which a substance freezes is known as its freezing point. Freezing point is a physical property of matter. The freezing point of pure water is 0 C. Below this temperature, water exists as ice. Above this temperature, it exists as liquid water or water vapor. Many other substances have much lower or higher freezing points than water. You can see some examples in the Table 1.1. The freezing point of pure water is included in the table for comparison. Substance Helium Oxygen Nitrogen Pure Water Lead Iron Carbon Freezing Point ( C) -272 -222 -210 0 328 1535 3500 Q: What trend do you see in this table? A: Substances in the table with freezing points lower than water are gases. Substances in the table with freezing points higher than water are solids. Q: Sodium is a solid at room temperature. Given this information, what can you infer about its freezing point? A: You can infer that the freezing point of sodium must be higher than room temperature, which is about 20 C. The freezing point of sodium is actually 98 C.


Output: which of these substances has the highest freezing point?