TASK DEFINITION: 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.
PROBLEM: Passage: For instance, a phased array consists of two or more simple antennas which are connected together through an electrical network. This often involves a number of parallel dipole antennas with a certain spacing. Depending on the relative phase introduced by the network, the same combination of dipole antennas can operate as a "broadside array" (directional normal to a line connecting the elements) or as an "end-fire array" (directional along the line connecting the elements). Antenna arrays may employ any basic (omnidirectional or weakly directional) antenna type, such as dipole, loop or slot antennas. These elements are often identical. Question: How many antenna would make up a phased array?

SOLUTION: two or more

PROBLEM: Passage: The City of Charleston is served by the Charleston International Airport. It is located in the City of North Charleston and is about 12 miles (20 km) northwest of downtown Charleston. It is the busiest passenger airport in South Carolina (IATA: CHS, ICAO: KCHS). The airport shares runways with the adjacent Charleston Air Force Base. Charleston Executive Airport is a smaller airport located in the John's Island section of the city of Charleston and is used by noncommercial aircraft. Both airports are owned and operated by the Charleston County Aviation Authority. Question: Charleston Executive Airport is located where?

SOLUTION: the John's Island section of the city of Charleston

PROBLEM: Passage: Short-distance passerine migrants have two evolutionary origins. Those that have long-distance migrants in the same family, such as the common chiffchaff Phylloscopus collybita, are species of southern hemisphere origins that have progressively shortened their return migration to stay in the northern hemisphere. Question: Why have some specied progressively shortened their return migration?

SOLUTION:
to stay in the northern hemisphere