This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Input: Consider Input: Passage: Hisham suffered still worse defeats in the east, where his armies attempted to subdue both Tokharistan, with its center at Balkh, and Transoxiana, with its center at Samarkand. Both areas had already been partially conquered, but remained difficult to govern. Once again, a particular difficulty concerned the question of the conversion of non-Arabs, especially the Sogdians of Transoxiana. Following the Umayyad defeat in the "Day of Thirst" in 724, Ashras ibn 'Abd Allah al-Sulami, governor of Khurasan, promised tax relief to those Sogdians who converted to Islam, but went back on his offer when it proved too popular and threatened to reduce tax revenues. Discontent among the Khurasani Arabs rose sharply after the losses suffered in the Battle of the Defile in 731, and in 734, al-Harith ibn Surayj led a revolt that received broad backing from Arabs and natives alike, capturing Balkh but failing to take Merv. After this defeat, al-Harith's movement seems to have been dissolved, but the problem of the rights of non-Arab Muslims would continue to plague the Umayyads.

Output: Who suffered worse defeats in the west?


Input: Consider Input: Passage: External evidence is evidence of each physical witness, its date, source, and relationship to other known witnesses. Critics will often prefer the readings supported by the oldest witnesses. Since errors tend to accumulate, older manuscripts should have fewer errors. Readings supported by a majority of witnesses are also usually preferred, since these are less likely to reflect accidents or individual biases. For the same reasons, the most geographically diverse witnesses are preferred. Some manuscripts show evidence that particular care was taken in their composition, for example, by including alternative readings in their margins, demonstrating that more than one prior copy (exemplar) was consulted in producing the current one. Other factors being equal, these are the best witnesses. The role of the textual critic is necessary when these basic criteria are in conflict. For instance, there will typically be fewer early copies, and a larger number of later copies. The textual critic will attempt to balance these criteria, to determine the original text.

Output: External evidence is evidence of each physical witness, its date, source, relationship to other known witnesses, and what else? 


Input: Consider Input: Passage: Several barriers protect organisms from infection, including mechanical, chemical, and biological barriers. The waxy cuticle of many leaves, the exoskeleton of insects, the shells and membranes of externally deposited eggs, and skin are examples of mechanical barriers that are the first line of defense against infection. However, as organisms cannot be completely sealed from their environments, other systems act to protect body openings such as the lungs, intestines, and the genitourinary tract. In the lungs, coughing and sneezing mechanically eject pathogens and other irritants from the respiratory tract. The flushing action of tears and urine also mechanically expels pathogens, while mucus secreted by the respiratory and gastrointestinal tract serves to trap and entangle microorganisms.


Output: What kind of barrier does not protect organisms from infection?