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.
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Question: Passage: As the terrain is generally arid, the hills have mostly poor soil and support only cacti and succulent plants. During the rainy season the area turns green with vegetation and grass. The eastern part of the island is greener as it receives more rainfall. A 1994 survey has revealed several hundred indigenous species of plants including the naturalized varieties of flora; some growing in irrigated areas while the dry areas are dominated by the cacti variety. Sea grapes and palm trees are a common sight with mangroves and shrubs surviving in the saline coastal swamps. Coconut palm was brought to the island from the Pacific islands. Important plants noted on the island are:

Answer: In what year was Coconut palm brought to the island?


Question: Passage: Land-based steam engines could exhaust much of their steam, as feed water was usually readily available. Prior to and during World War I, the expansion engine dominated marine applications where high vessel speed was not essential. It was however superseded by the British invention steam turbine where speed was required, for instance in warships, such as the dreadnought battleships, and ocean liners. HMS Dreadnought of 1905 was the first major warship to replace the proven technology of the reciprocating engine with the then-novel steam turbine.[citation needed]

Answer: The frequent availability of what substance allowed land-based steam engines to exhaust a great deal of battleships?


Question: Passage: Mary is referred to by the Eastern Orthodox Church, Oriental Orthodoxy, the Anglican Church, and all Eastern Catholic Churches as Theotokos, a title recognized at the Third Ecumenical Council (held at Ephesus to address the teachings of Nestorius, in 431). Theotokos (and its Latin equivalents, "Deipara" and "Dei genetrix") literally means "Godbearer". The equivalent phrase "Mater Dei" (Mother of God) is more common in Latin and so also in the other languages used in the Western Catholic Church, but this same phrase in Greek (Μήτηρ Θεοῦ), in the abbreviated form of the first and last letter of the two words (ΜΡ ΘΥ), is the indication attached to her image in Byzantine icons. The Council stated that the Church Fathers "did not hesitate to speak of the holy Virgin as the Mother of God".

Answer:
In what year did Mary attend the Third Ecumenical Council?