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

Example Input: 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:
Example Output: the source of solar power is nuclear

Example Input: The antiparallel side-to-side association of spectrin alpha and beta monomers is a two-step process which occurs in seconds even at 0 degrees C and at low concentrations. Assembly involves initial contact of complementary nucleation sites on each subunit, which are located near the actin binding end of the long, flexible heterodimer rod. The minimum nucleation sites are comprised of approximately four contiguous 106-residue homologous segments or repeats. Three repeats in the nucleation site contain an 8-residue insertion and have the highest homology to the four spectrin-like repeats in alpha-actinin. The adjacent actin binding domain on the beta subunit and the adjacent EF hand motifs on the alpha subunit are not required for heterodimer assembly. The nucleation sites probably have a specific lock and key structure which defines the unique side-to-side pairing of the many homologous segments in both subunits. Assembly of spectrin heterodimers is probably most analogous to a zipper. After initial nucleation site binding, the remainder of the subunits quickly associate along their full lengths to reconstitute a normal dimer by supercoiling around each other to form a rope-like, flexible rod. Assembly is terminated if either polypeptide is interrupted by a protease cleavage. Heterozygotic mutations involving either nucleation site are predicted to affect allele incorporation into the mature membrane skeleton.
Example Output: Alpha-spectrin and beta-spectrin subunits form parallel or antiparallel heterodimers?

Example Input: Henry Shutes (1804 -- September 10, 1889) was a Union Navy sailor in the American Civil War and a recipient of the U.S. military's highest decoration, the Medal of Honor, for his actions at the Battle of Forts Jackson and St. Philip and an 1863 engagement with Fort McAllister, Georgia.
Example Output:
What military branch was Henry Shutes associated with?