TASK DEFINITION: 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.
PROBLEM: Passage: Although anthropologists worldwide refer to Tylor's definition of culture, in the 20th century "culture" emerged as the central and unifying concept of American anthropology, where it most commonly refers to the universal human capacity to classify and encode human experiences symbolically, and to communicate symbolically encoded experiences socially.[citation needed] American anthropology is organized into four fields, each of which plays an important role in research on culture: biological anthropology, linguistic anthropology, cultural anthropology, and archaeology.

SOLUTION: Who's definition of culture did anthropologists reject?

PROBLEM: Passage: The terms used to define Greekness have varied throughout history but were never limited or completely identified with membership to a Greek state. By Western standards, the term Greeks has traditionally referred to any native speakers of the Greek language, whether Mycenaean, Byzantine or modern Greek. Byzantine Greeks called themselves Romioi and considered themselves the political heirs of Rome, but at least by the 12th century a growing number of those educated, deemed themselves the heirs of ancient Greece as well, although for most of the Greek speakers, "Hellene" still meant pagan. On the eve of the Fall of Constantinople the Last Emperor urged his soldiers to remember that they were the descendants of Greeks and Romans.

SOLUTION: What do Easterners believe it means to belong to the Greek heritage

PROBLEM: Passage: The period known as the Crusades, a series of religiously motivated military expeditions originally intended to bring the Levant back into Christian rule, began. Several Crusader states were founded in the eastern Mediterranean. These were all short-lived. The Crusaders would have a profound impact on many parts of Europe. Their Sack of Constantinople in 1204 brought an abrupt end to the Byzantine Empire. Though it would later be re-established, it would never recover its former glory. The Crusaders would establish trade routes that would develop into the Silk Road and open the way for the merchant republics of Genoa and Venice to become major economic powers. The Reconquista, a related movement, worked to reconquer Iberia for Christendom.

SOLUTION:
What is the name of the period of peaceful incursions undertaken in the name of Christianity?