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: 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: the source of solar power is nuclear
[A]: fusion.


[Q]: Context: In America, when the eighth graders leave the middle school, they are often worried about moving to the high school. It is a hard time for them, but it can be an exciting one as well. To make it easier, students need to get familiar with their school. Even though they've done this already in the middle school, it's still important to find where their classrooms are. Most schools take students to the high school for a visit at the end of their eighth grade year. And, most schools also have a freshman speech for parents and students before the first year begins. Sometimes the main office will give away a map of the school. This can help students and parents to find different places in the school. One way to know your high school more and make new friends is to join a club or play a sport. Schools often offer chances to join different clubs and sports. Fall activities begin in August before the first day of school. If you are not interested in sports, there are clubs for any interest, such as drama, dance, chess, photography, community service, etc. These clubs allow students from different grades. By joining an activity, students can find new friendships, not to mention improving their chances in future college applications . The school office will have a list of activities offered at the school and information on how to join them. What's more, to have a great start to a high school year, students can write down some of their worries, and ask for help from teachers and school workers. 
 Question: When do many schools take students to visit their new high school?
[A]: at the end of their eighth grade year


[Q]: Context: Mutations in NOTCH3 are the cause of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a hereditary angiopathy causing stroke and vascular dementia. All CADASIL mutations identified so far result in the loss or gain of one cysteine residue within epidermal growth factor (EGF)-like repeat domains. Here an in-frame deletion causing a loss of three cysteine residues within EGF repeat 6 is reported. These data are consistent with the hypothesis that the change toward an odd number of cysteine residues within a given EGF repeat and therefore an unpaired, reactive cysteine residue is the common and critical molecular event in CADASIL. 
 Question: Which amino acid residue appears mutated in most of the cases reported with cadasil syndrome?
[A]:
cysteine