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: An electromagnetic wave refractor in some aperture antennas is a component which due to its shape and position functions to selectively delay or advance portions of the electromagnetic wavefront passing through it. The refractor alters the spatial characteristics of the wave on one side relative to the other side. It can, for instance, bring the wave to a focus or alter the wave front in other ways, generally in order to maximize the directivity of the antenna system. This is the radio equivalent of an optical lens. Question: What is used to allow one to control the function of wave fronts moving through an antenna?

Ex Output:
selectively delay


Ex Input:
Passage: The dominant land plant species of the time were gymnosperms, which are vascular, cone-bearing, non-flowering plants such as conifers that produce seeds without a coating. This is opposed to the earth's current flora, in which the dominant land plants in terms of number of species are angiosperms. One particular plant genus, Ginkgo, is thought to have evolved at this time and is represented today by a single species, Ginkgo biloba. As well, the extant genus Sequoia is believed to have evolved in the Mesozoic. Question: What was the dominant plant species of the Mesozoic?

Ex Output:
gymnosperms


Ex Input:
Passage: Bernanke explained that between 1996 and 2004, the U.S. current account deficit increased by $650 billion, from 1.5% to 5.8% of GDP. Financing these deficits required the country to borrow large sums from abroad, much of it from countries running trade surpluses. These were mainly the emerging economies in Asia and oil-exporting nations. The balance of payments identity requires that a country (such as the U.S.) running a current account deficit also have a capital account (investment) surplus of the same amount. Hence large and growing amounts of foreign funds (capital) flowed into the U.S. to finance its imports. Question: What emerging economies did the U.S. borrow money from between 1996 and 2004 to finance its imports?

Ex Output:

Asia and oil-exporting nations