Question: Apart from residences for upper and middle class households, sanitation is insufficient in most residential areas. Private flush toilets are too expensive for virtually all residents in townships due to their water consumption and installation cost. As a result, access to improved sanitation has not increased much since independence: In Namibia's rural areas 13% of the population had more than basic sanitation, up from 8% in 1990. Many of Namibia's inhabitants have to resort to "flying toilets", plastic bags to defecate which after use are flung into the bush. The use of open areas close to residential land to urinate and defecate is very common and has been identified as a major health hazard.
Is there an answer to this question: In what year did Namibia's rural areas have 13% of the population with more than basic sanitation?

Answer: unanswerable

Question: However, by the turn of the 1990s the downward trend was starting to reverse; England had been successful in the 1990 FIFA World Cup, reaching the semi-finals. UEFA, European football's governing body, lifted the five-year ban on English clubs playing in European competitions in 1990 (resulting in Manchester United lifting the UEFA Cup Winners' Cup in 1991) and the Taylor Report on stadium safety standards, which proposed expensive upgrades to create all-seater stadiums in the aftermath of the Hillsborough disaster, was published in January of that year.
Is there an answer to this question: In which year was the ninety year ban on English clubs lifted?

Answer: unanswerable

Question: After the success of quantum electrodynamics, Feynman turned to quantum gravity. By analogy with the photon, which has spin 1, he investigated the consequences of a free massless spin 2 field, and derived the Einstein field equation of general relativity, but little more. The computational device that Feynman discovered then for gravity, "ghosts", which are "particles" in the interior of his diagrams that have the "wrong" connection between spin and statistics, have proved invaluable in explaining the quantum particle behavior of the YangMills theories, for example, QCD and the electro-weak theory.
Is there an answer to this question: What did Feynman's discoveries hurt the explanation of?

Answer: unanswerable

Question: Symbiosis (from Greek "together" and "living") is close and often long-term interaction between two different biological species. In 1877 Albert Bernhard Frank used the word symbiosis (which previously had been used to depict people living together in community) to describe the mutualistic relationship in lichens. In 1879, the German mycologist Heinrich Anton de Bary defined it as "the living together of unlike organisms."
Is there an answer to this question: What nationality was Heinrich Anton de Bary?

Answer:
German