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Directions : Read the passage given below and answer the questions that follow (Q. No. 320 to 325) by selecting the correct/most appropriate options. Did you know that there is a fiber that is as flexible and lightweight as nylon yet five times stronger than steel? Did you know that this fabric is resistant to temperatures higher than 500 degrees Fahrenheit? Did you know that a woman invented this fiber? This miraculous fabric is called Kevlar and it is used to make everything from body armor to musical instruments. The year was 1964. There were gasoline shortages due to conflict in the Middle East. A Polish-American chemist named Stephanie Louise Kwolek was working for DuPont, an American chemical company. She and her group were trying to make a lightweight, yet durable fiber to be used in tires. Lighter tires would allow vehicles to get better gas mileage, but the tires had to be strong enough to resist the wear and tear of the road. They had been working on the probelm for some time and had little success, until Kwolek had a breakthrough. Kwolek and her group were synthesizing or creating fibers to test. During one of the steps in the process, Kwolek created a milky white solution by mixing two chemicals that were often used in the process. This solution was usually thrown away, but Kwolek convinced one of the technicians to help her test it. They were amazed to discover that the fabric that Kwolek had created was not only more durable than nylon, it was more durable than steel. Kwolek had invented Kevlar. Kevlar is a remarkable fabric known for its strength and durability. Since its invention has found its way into a wide variety of products. Kevlar is used in sporting equipment like bike tires, bowstrings and tennis racquets. It is used in musical instruments like drumheads, reeds and speaker cones. And it is used in protective gear like motorcycle afety jackets, glove and shoes. However, Kevlar is best known for its ability to stop bullets. Richard Armellino created the first Kevlar bulletproof vest in 1975. It contained 15 layers of Kevlar, which could stop handgun and shotgun bullets. The vest also had a steel plate over the heart, which made the vest strong enough to stop rifle rounds. Vests like Armellino's were quickly picked up by police froces and it is estimated that by 1990, half of all police officers in America wore bulletproof vests daily. By 2006, there were over 2000 documented police vest 'saves', or instances where officers were protected form deadly wounds by wearing bulletproof vests. What product was Kwolek trying to improve when she invented Kevlar?
