This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
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Question: Most light bulbs have either clear or coated glass. The coated glass bulbs have a white powdery substance on the inside called kaolin. Kaolin, or kaolinite, is a white, chalky clay in a very fine powder form, that is blown in and electrostatically deposited on the interior of the bulb. It diffuses the light emitted from the filament, producing a more gentle and evenly distributed light. Manufacturers may add pigments to the kaolin to adjust the characteristics of the final light emitted from the bulb. Kaolin diffused bulbs are used extensively in interior lighting because of their comparatively gentle light. Other kinds of colored bulbs are also made, including the various colors used for "party bulbs", Christmas tree lights and other decorative lighting. These are created by coloring the glass with a dopant; which is often a metal like cobalt (blue) or chromium (green). Neodymium-containing glass is sometimes used to provide a more natural-appearing light.

Answer: What is the powdery substance in coated glass light bulbs?


Question: Certain genera of Gram-positive bacteria, such as Bacillus, Clostridium, Sporohalobacter, Anaerobacter, and Heliobacterium, can form highly resistant, dormant structures called endospores. In almost all cases, one endospore is formed and this is not a reproductive process, although Anaerobacter can make up to seven endospores in a single cell. Endospores have a central core of cytoplasm containing DNA and ribosomes surrounded by a cortex layer and protected by an impermeable and rigid coat. Dipicolinic acid is a chemical compound that composes 5% to 15% of the dry weight of bacterial spores. It is implicated as responsible for the heat resistance of the endospore.

Answer: What are highly resistant dormant structures of certain gram-positive bacteria called?


Question: The geographical regions in which Iranian languages were spoken were pushed back in several areas by newly neighbouring languages. Arabic spread into some parts of Western Iran (Khuzestan), and Turkic languages spread through much of Central Asia, displacing various Iranian languages such as Sogdian and Bactrian in parts of what is today Turkmenistan, Uzbekistan and Tajikistan. In Eastern Europe, mostly comprising the territory of modern-day Ukraine, southern European Russia, and parts of the Balkans, the core region of the native Scythians, Sarmatians, and Alans had been decisively been taken over as a result of absorption and assimilation (e.g. Slavicisation) by the various Proto-Slavic population of the region, by the 6th century AD. This resulted in the displacement and extinction of the once predominant Scythian languages of the region. Sogdian's close relative Yaghnobi barely survives in a small area of the Zarafshan valley east of Samarkand, and Saka as Ossetic in the Caucasus, which is the sole remnant of the once predominant Scythian languages in Eastern Europe proper and large parts of the North Caucasus. Various small Iranian languages in the Pamirs survive that are derived from Eastern Iranian.

Answer:
What is another term for Western Iran?