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: The double indirect method can be used when it is important to see the work during the creation process as it will appear when completed. The tesserae are placed face-up on a medium (often adhesive-backed paper, sticky plastic or soft lime or putty) as it will appear when installed. When the mosaic is complete, a similar medium is placed atop it. The piece is then turned over, the original underlying material is carefully removed, and the piece is installed as in the indirect method described above. In comparison to the indirect method, this is a complex system to use and requires great skill on the part of the operator, to avoid damaging the work. Its greatest advantage lies in the possibility of the operator directly controlling the final result of the work, which is important e.g. when the human figure is involved. This method was created in 1989 by Maurizio Placuzzi and registered for industrial use (patent n. 0000222556) under the name of his company, Sicis International Srl, now Sicis The Art Mosaic Factory Srl.

Answer: When is the double indirect method of mosaic useful?

Question: The brushless wound-rotor synchronous doubly-fed (BWRSDF) machine is the only electric machine with a truly dual ported transformer circuit topology (i.e., both ports independently excited with no short-circuited port). The dual ported transformer circuit topology is known to be unstable and requires a multiphase slip-ring-brush assembly to propagate limited power to the rotor winding set. If a precision means were available to instantaneously control torque angle and slip for synchronous operation during motoring or generating while simultaneously providing brushless power to the rotor winding set, the active current of the BWRSDF machine would be independent of the reactive impedance of the transformer circuit and bursts of torque significantly higher than the maximum operating torque and far beyond the practical capability of any other type of electric machine would be realizable. Torque bursts greater than eight times operating torque have been calculated.

Answer: What is the only device with dual ported transformer circuit topology?

Question: There are approximately ten times as many bacterial cells in the human flora as there are human cells in the body, with the largest number of the human flora being in the gut flora, and a large number on the skin. The vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, and some are beneficial. However, several species of bacteria are pathogenic and cause infectious diseases, including cholera, syphilis, anthrax, leprosy, and bubonic plague. The most common fatal bacterial diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year, mostly in sub-Saharan Africa. In developed countries, antibiotics are used to treat bacterial infections and are also used in farming, making antibiotic resistance a growing problem. In industry, bacteria are important in sewage treatment and the breakdown of oil spills, the production of cheese and yogurt through fermentation, and the recovery of gold, palladium, copper and other metals in the mining sector, as well as in biotechnology, and the manufacture of antibiotics and other chemicals.

Answer:
What is the ratio of human/bacteria cells in human flora?