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.

Ex Input:
Passage: As with most of Europe, prehistoric Britain and Ireland were covered with forest and swamp. Clearing began around 6000 BC and accelerated in medieval times. Despite this, Britain retained its primeval forests longer than most of Europe due to a small population and later development of trade and industry, and wood shortages were not a problem until the 17th century. By the 18th century, most of Britain's forests were consumed for shipbuilding or manufacturing charcoal and the nation was forced to import lumber from Scandinavia, North America, and the Baltic. Most forest land in Ireland is maintained by state forestation programmes. Almost all land outside urban areas is farmland. However, relatively large areas of forest remain in east and north Scotland and in southeast England. Oak, elm, ash and beech are amongst the most common trees in England. In Scotland, pine and birch are most common. Natural forests in Ireland are mainly oak, ash, wych elm, birch and pine. Beech and lime, though not native to Ireland, are also common there. Farmland hosts a variety of semi-natural vegetation of grasses and flowering plants. Woods, hedgerows, mountain slopes and marshes host heather, wild grasses, gorse and bracken.

Ex Output:
Ice and snow covered prehistoric Britain and what other country?

Ex Input:
Passage: Mali lies in the torrid zone and is among the hottest countries in the world. The thermal equator, which matches the hottest spots year-round on the planet based on the mean daily annual temperature, crosses the country. Most of Mali receives negligible rainfall and droughts are very frequent. Late June to early December is the rainy season in the southernmost area. During this time, flooding of the Niger River is common, creating the Inner Niger Delta. The vast northern desert part of Mali has a hot desert climate (Koppen climate classification (BWh) with long, extremely hot summers and scarce rainfall which decreases northwards. The central area has a hot semi-arid climate (Koppen climate classification (BSh) with very high temperatures year-round, a long, intense dry season and a brief, irregular rainy season. The little southern band possesses a tropical wet and dry climate (Koppen climate classification (Aw) very high temperatures year-round with a dry season and a rainy season.

Ex Output:
What is in the tropical zone?

Ex Input:
Passage: An alloy is a mixture of either pure or fairly pure chemical elements, which forms an impure substance (admixture) that retains the characteristics of a metal. An alloy is distinct from an impure metal, such as wrought iron, in that, with an alloy, the added impurities are usually desirable and will typically have some useful benefit. Alloys are made by mixing two or more elements; at least one of which being a metal. This is usually called the primary metal or the base metal, and the name of this metal may also be the name of the alloy. The other constituents may or may not be metals but, when mixed with the molten base, they will be soluble, dissolving into the mixture.

Ex Output:
What is a mixture of impure substances?