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.
--------
Question: Passage: Naturally occurring glass, especially the volcanic glass obsidian, has been used by many Stone Age societies across the globe for the production of sharp cutting tools and, due to its limited source areas, was extensively traded. But in general, archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or ancient Egypt. The earliest known glass objects, of the mid third millennium BCE, were beads, perhaps initially created as accidental by-products of metal-working (slags) or during the production of faience, a pre-glass vitreous material made by a process similar to glazing. Question: What was obsidian used to make in prehistoric times?

Answer: cutting tools


Question: Passage: Chopin has figured extensively in Polish literature, both in serious critical studies of his life and music and in fictional treatments. The earliest manifestation was probably an 1830 sonnet on Chopin by Leon Ulrich. French writers on Chopin (apart from Sand) have included Marcel Proust and André Gide; and he has also featured in works of Gottfried Benn and Boris Pasternak. There are numerous biographies of Chopin in English (see bibliography for some of these). Question: An 1830 sonnet was written about Chopin by what man?

Answer: Leon Ulrich


Question: Passage: After World War I the US Army started developing a dual-role (AA/ground) automatic 37 mm cannon, designed by John M. Browning. It was standardised in 1927 as the T9 AA cannon, but trials quickly revealed that it was worthless in the ground role. However, while the shell was a bit light (well under 2 lbs) it had a good effective ceiling and fired 125 rounds per minute; an AA carriage was developed and it entered service in 1939. The Browning 37mm proved prone to jamming, and was eventually replaced in AA units by the Bofors 40 mm. The Bofors had attracted attention from the US Navy, but none were acquired before 1939. Also, in 1931 the US Army worked on a mobile anti-aircraft machine mount on the back of a heavy truck having four .30 caliber water-cooled machine guns and an optical director. It proved unsuccessful and was abandoned. Question: What other US group was interested in the Bofors?

Answer:
US Navy