Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Within computer systems, two of many security models capable of enforcing privilege separation are access control lists (ACLs) and capability-based security. Using ACLs to confine programs has been proven to be insecure in many situations, such as if the host computer can be tricked into indirectly allowing restricted file access, an issue known as the confused deputy problem. It has also been shown that the promise of ACLs of giving access to an object to only one person can never be guaranteed in practice. Both of these problems are resolved by capabilities. This does not mean practical flaws exist in all ACL-based systems, but only that the designers of certain utilities must take responsibility to ensure that they do not introduce flaws.[citation needed]
A host computer tricked into indirectly allowing access to restricted files is known as what?
A: the confused deputy problem

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Much of the medieval period was a time of power struggles between competing dynasties such as the House of Savoy, the Visconti in northern Italy and the House of Habsburg in Austria and Slovenia. In 1291 to protect themselves from incursions by the Habsburgs, four cantons in the middle of Switzerland drew up a charter that is considered to be a declaration of independence from neighboring kingdoms. After a series of battles fought in the 13th, 14th and 15th centuries, more cantons joined the confederacy and by the 16th century Switzerland was well-established as a separate state.
Much of the medieval period was a time of what?
A: power struggles

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A variety of industries benefit from hunting and support hunting on economic grounds. In Tanzania, it is estimated that a safari hunter spends fifty to one hundred times that of the average ecotourist. While the average photo tourist may seek luxury accommodation, the average safari hunter generally stays in tented camps. Safari hunters are also more likely to use remote areas, uninviting to the typical ecotourist. Advocates argue that these hunters allow for anti-poaching activities and revenue for local communities.[citation needed]
Where does the typical safari hunter hang his hat at night?
A: in tented camps

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Greenhouses convert solar light to heat, enabling year-round production and the growth (in enclosed environments) of specialty crops and other plants not naturally suited to the local climate. Primitive greenhouses were first used during Roman times to produce cucumbers year-round for the Roman emperor Tiberius. The first modern greenhouses were built in Europe in the 16th century to keep exotic plants brought back from explorations abroad. Greenhouses remain an important part of horticulture today, and plastic transparent materials have also been used to similar effect in polytunnels and row covers.
Where were the first modern greenhouses built?
A:
Europe