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: In New York City in 1846, Alexander Turney Stewart established the "Marble Palace" on Broadway, between Chambers and Reade streets. He offered European retail merchandise at fixed prices on a variety of dry goods, and advertised a policy of providing "free entrance" to all potential customers. Though it was clad in white marble to look like a Renaissance palazzo, the building's cast iron construction permitted large plate glass windows that permitted major seasonal displays, especially in the Christmas shopping season. In 1862, Stewart built a new store on a full city block with eight floors and nineteen departments of dress goods and furnishing materials, carpets, glass and china, toys and sports equipment, ranged around a central glass-covered court. His innovations included buying from manufacturers for cash and in large quantities, keeping his markup small and prices low, truthful presentation of merchandise, the one-price policy (so there was no haggling), simple merchandise returns and cash refund policy, selling for cash and not credit, buyers who searched worldwide for quality merchandise, departmentalization, vertical and horizontal integration, volume sales, and free services for customers such as waiting rooms and free delivery of purchases. His innovations were quickly copied by other department stores. Question: What policy did the Marble Palace introduce? 
[A]: "free entrance" to all potential customers.


[Q]: Passage: Another potential weapon system for anti-aircraft use is the laser. Although air planners have imagined lasers in combat since the late 1960s, only the most modern laser systems are currently reaching what could be considered "experimental usefulness". In particular the Tactical High Energy Laser can be used in the anti-aircraft and anti-missile role. If current developments continue, some[who?] believe it is reasonable to suggest that lasers will play a major role in air defence starting in the next ten years. Question: When do some people believe that lasers can play a more prominent role in air defence?
[A]: in the next ten years


[Q]: Passage: Phonetically in some languages, such as Navajo, aspiration of stops tends to be realised as voiceless velar airflow; aspiration of affricates is realised as an extended length of the frication. Question: In Navajo, the aspiration of affricates can be seen as what?
[A]:
an extended length of the frication