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: A series of experiments performed from the late 1800s to the early 1900s revealed that diabetes is caused by the absence of a substance normally produced by the pancreas. In 1869, Oskar Minkowski and Joseph von Mering found that diabetes could be induced in dogs by surgical removal of the pancreas. In 1921, Canadian professor Frederick Banting and his student Charles Best repeated this study, and found that injections of pancreatic extract reversed the symptoms produced by pancreas removal. Soon, the extract was demonstrated to work in people, but development of insulin therapy as a routine medical procedure was delayed by difficulties in producing the material in sufficient quantity and with reproducible purity. The researchers sought assistance from industrial collaborators at Eli Lilly and Co. based on the company's experience with large scale purification of biological materials. Chemist George Walden of Eli Lilly and Company found that careful adjustment of the pH of the extract allowed a relatively pure grade of insulin to be produced. Under pressure from Toronto University and a potential patent challenge by academic scientists who had independently developed a similar purification method, an agreement was reached for non-exclusive production of insulin by multiple companies. Prior to the discovery and widespread availability of insulin therapy the life expectancy of diabetics was only a few months. Question: Who discovered that pancreatic extract reversed symptoms of pancreas removal?

A: Frederick Banting and his student Charles Best
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Q: 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?

A: selectively delay
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Q: Passage: As a landlocked country Tajikistan has no ports and the majority of transportation is via roads, air, and rail. In recent years Tajikistan has pursued agreements with Iran and Pakistan to gain port access in those countries via Afghanistan. In 2009, an agreement was made between Tajikistan, Pakistan, and Afghanistan to improve and build a 1,300 km (810 mi) highway and rail system connecting the three countries to Pakistan's ports. The proposed route would go through the Gorno-Badakhshan Autonomous Province in the eastern part of the country. And in 2012, the presidents of Tajikistan, Afghanistan, and Iran signed an agreement to construct roads and railways as well as oil, gas, and water pipelines to connect the three countries. Question: What are the majority of transportation options?

A:
via roads, air, and rail.
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