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.

Q: Passage: Later, the constitution was amended to state that the citizens of the 16 states had successfully achieved the unity of Germany in free self-determination and that the Basic Law thus applied to the entire German people. Article 23, which had allowed "any other parts of Germany" to join, was rephrased. It had been used in 1957 to reintegrate the Saar Protectorate as the Saarland into the Federal Republic, and this was used as a model for German reunification in 1990. The amended article now defines the participation of the Federal Council and the 16 German states in matters concerning the European Union.

A: What was amended to signify that Basic Law no longer applied to the German people?
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Q: Passage: When Estonia was invaded and occupied by the Soviet Union in World War II, the status of the Estonian language changed to the first of two official languages (Russian being the other one). As with Latvia many immigrants entered Estonia under Soviet encouragement. In the second half of the 1970s, the pressure of bilingualism (for Estonians) intensified, resulting in widespread knowledge of Russian throughout the country. The Russian language was termed as 'the language of friendship of nations' and was taught to Estonian children, sometimes as early as in kindergarten. Although teaching Estonian to non-Estonians in schools was compulsory, in practice learning the language was often considered unnecessary.

A: What country did not occupy Estonia?
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Q: Passage: The mechanisms used to evade the adaptive immune system are more complicated. The simplest approach is to rapidly change non-essential epitopes (amino acids and/or sugars) on the surface of the pathogen, while keeping essential epitopes concealed. This is called antigenic variation. An example is HIV, which mutates rapidly, so the proteins on its viral envelope that are essential for entry into its host target cell are constantly changing. These frequent changes in antigens may explain the failures of vaccines directed at this virus. The parasite Trypanosoma brucei uses a similar strategy, constantly switching one type of surface protein for another, allowing it to stay one step ahead of the antibody response. Masking antigens with host molecules is another common strategy for avoiding detection by the immune system. In HIV, the envelope that covers the virion is formed from the outermost membrane of the host cell; such "self-cloaked" viruses make it difficult for the immune system to identify them as "non-self" structures.

A:
What are the less complex mechanisms used to do?
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