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.

[Q]: Passage: Most migrations begin with the birds starting off in a broad front. Often, this front narrows into one or more preferred routes termed flyways. These routes typically follow mountain ranges or coastlines, sometimes rivers, and may take advantage of updrafts and other wind patterns or avoid geographical barriers such as large stretches of open water. The specific routes may be genetically programmed or learned to varying degrees. The routes taken on forward and return migration are often different. A common pattern in North America is clockwise migration, where birds flying North tend to be further West, and flying South tend to shift Eastwards. Question: What obsticals will migrating birds avoid?
[A]: large stretches of open water


[Q]: Passage: The inventor Nicéphore Niépce produced the first permanent photograph on a polished pewter plate in Paris in 1825, and then developed the process with Louis Daguerre. The work of Étienne-Jules Marey in the 1880s contributed considerably to the development of modern photography. Photography came to occupy a central role in Parisian Surrealist activity, in the works of Man Ray and Maurice Tabard. Numerous photographers achieved renown for their photography of Paris, including Eugène Atget, noted for his depictions of street scenes, Robert Doisneau, noted for his playful pictures of people and market scenes (among which Le baiser de l'hôtel de ville has became iconic of the romantic vision of Paris), Marcel Bovis, noted for his night scenes, and others such as Jacques-Henri Lartigue and Cartier-Bresson. Poster art also became an important art form in Paris in the late nineteenth century, through the work of Henri de Toulouse-Lautrec, Jules Chéret, Eugène Grasset, Adolphe Willette, Pierre Bonnard, Georges de Feure, Henri-Gabriel Ibels, Gavarni, and Alphonse Mucha. Question: Who was knows for photographing night scenes?
[A]: Marcel Bovis


[Q]: Passage: It was only in the 1980s that digital telephony transmission networks became possible, such as with ISDN networks, assuring a minimum bit rate (usually 128 kilobits/s) for compressed video and audio transmission. During this time, there was also research into other forms of digital video and audio communication. Many of these technologies, such as the Media space, are not as widely used today as videoconferencing but were still an important area of research. The first dedicated systems started to appear in the market as ISDN networks were expanding throughout the world. One of the first commercial videoconferencing systems sold to companies came from PictureTel Corp., which had an Initial Public Offering in November, 1984. Question: In what form did the first dedicated videoconferencing system appear as?
[A]:
ISDN networks