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

Example Input: The height of a wave is its amplitude. Another measure of wave size is wavelength. Both wave amplitude and wave- length are described in detail below. Figure 19.11 shows these wave measures for both transverse and longitudinal waves. You can also simulate waves with different amplitudes and wavelengths by doing the interactive animation at this URL: [Link] . Wave amplitude is the maximum distance the particles of a medium move from their resting position when a wave passes through. The resting position is where the particles would be in the absence of a wave. In a transverse wave, wave amplitude is the height of each crest above the resting position. The higher the crests are, the greater the amplitude. In a longitudinal wave, amplitude is a measure of how compressed particles of the medium become when the wave passes through. The closer together the particles are, the greater the amplitude. What determines a waves amplitude? It depends on the energy of the disturbance that causes the wave. A wave caused by a disturbance with more energy has greater amplitude. Imagine dropping a small pebble into a pond of still water. Tiny ripples will move out from the disturbance in concentric circles, like those in Figure 19.1. The ripples are low-amplitude waves. Now imagine throwing a big boulder into the pond. Very large waves will be generated by the disturbance. These waves are high-amplitude waves. Another important measure of wave size is wavelength. Wavelength is the distance between two corresponding points on adjacent waves (see Figure 19.11). Wavelength can be measured as the distance between two adjacent crests of a transverse wave or two adjacent compressions of a longitudinal wave. It is usually measured in meters. Wavelength is related to the energy of a wave. Short-wavelength waves have more energy than long-wavelength waves of the same amplitude. You can see examples of waves with shorter and longer wavelengths in Figure 19.12. Imagine making transverse waves in a rope, like the waves in Figure 19.2. You tie one end of the rope to a doorknob or other fixed point and move the other end up and down with your hand. You can move the rope up and down slowly or quickly. How quickly you move the rope determines the frequency of the waves. The number of waves that pass a fixed point in a given amount of time is wave frequency. Wave frequency can be measured by counting the number of crests or compressions that pass the point in 1 second or other time period. The higher the number is, the greater is the frequency of the wave. The SI unit for wave frequency is the hertz (Hz), where 1 hertz equals 1 wave passing a fixed point in 1 second. Figure 19.13 shows high-frequency and low- frequency transverse waves. You can simulate transverse waves with different frequencies at this URL: [Link] The frequency of a wave is the same as the frequency of the vibrations that caused the wave. For example, to generate a higher-frequency wave in a rope, you must move the rope up and down more quickly. This takes more energy, so a higher-frequency wave has more energy than a lower-frequency wave with the same amplitude. Assume that you move one end of a rope up and down just once. How long will take the wave to travel down the rope to the other end? This depends on the speed of the wave. Wave speed is how far the wave travels in a given amount of time, such as how many meters it travels per second. Wave speed is not the same thing as wave frequency, but it is related to frequency and also to wavelength. This equation shows how the three factors are related: Speed = Wavelength Frequency In this equation, wavelength is measured in meters and frequency is measured in hertz, or number of waves per second. Therefore, wave speed is given in meters per second. The equation for wave speed can be used to calculate the speed of a wave when both wavelength and wave frequency are known. Consider an ocean wave with a wavelength of 3 meters and a frequency of 1 hertz. The speed of the wave is: Speed = 3
Example Output: SI unit for wave frequency

Example Input: An Australian inventor has designed and built an environmentally friendly ferry that uses solar and wind power to transport people around Sydney Harbor. Robert Dane and his Solar Sailor were given the top prize at the Australian Design Awards recently. The Solar Sailor has been in use for six months. It uses four sources of energy for its power -- solar, wind, battery power with stored solar energy and a fuel generator in store all controlled by computers. The ferry can travel up to 7.5 knots on just wind and solar power. It's solar wings and fiberglass solar panels which not only take in sunlight and store it in batteries, but also act as sails. "We angle our solar panels to the sun in two planes , which increases the amount of energy we get from the sun by 40 percent," Dane says. "And also we can use that same structure to do another job, which is also the sail, and so these wing sails actually push the ferry forward just like a soft sail does." Computers check the sun and wind and angle the solar wings to take in the most sunlight. If there isn't much wind or it is a cloudy day, energy stored in the batteries runs the electric motor for up to five hours. "If the batteries are too low, then the computer turns the generator on so the boat is always able to meet a commercial schedule, or get from point A to point B no matter what," Dan explains. Dane got his idea for the Solar Sailor from a book on insects. He was amazed how insects use their wings to collect solar energy to warm themselves. "When I read that, I realized there was a good example in nature for what we were going to do, which was to use a solar wing to collect solar energy and also to sail," he says.
Example Output: What is the Solar Sailor?

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?

