This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Ex Input:
Passage: In the Romantic era, the modern piano, with a more powerful, sustained tone and a wider range took over from the more delicate-sounding fortepiano. In the orchestra, the existing Classical instruments and sections were retained (string section, woodwinds, brass and percussion), but these sections were typically expanded to make a fuller, bigger sound. For example, while a Baroque orchestra may have had two double bass players, a Romantic orchestra could have as many as ten. "As music grew more expressive, the standard orchestral palette just wasn't rich enough for many Romantic composers."  New woodwind instruments were added, such as the contrabassoon, bass clarinet and piccolo and new percussion instruments were added, including xylophones, drums, celestes (a bell-like keyboard instrument), large orchestral harps, bells, and triangles  and even wind machines for sound effects. Question: What is a celestes?

Ex Output:
a bell-like keyboard instrument


Ex Input:
Passage: The most popular Korean dog dish is gaejang-guk (also called bosintang), a spicy stew meant to balance the body's heat during the summer months; followers of the custom claim this is done to ensure good health by balancing one's gi, or vital energy of the body. A 19th century version of gaejang-guk explains that the dish is prepared by boiling dog meat with scallions and chili powder. Variations of the dish contain chicken and bamboo shoots. While the dishes are still popular in Korea with a segment of the population, dog is not as widely consumed as beef, chicken, and pork. Question: What is Gaejang-guk?

Ex Output:
a spicy stew


Ex Input:
Passage: The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage. Question: Up to what wavelength does the human eye perceive IR LED sources as red?

Ex Output:

780 nm