instruction:
Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.
question:
Passage: Many known complexity classes are suspected to be unequal, but this has not been proved. For instance P ⊆ NP ⊆ PP ⊆ PSPACE, but it is possible that P = PSPACE. If P is not equal to NP, then P is not equal to PSPACE either. Since there are many known complexity classes between P and PSPACE, such as RP, BPP, PP, BQP, MA, PH, etc., it is possible that all these complexity classes collapse to one class. Proving that any of these classes are unequal would be a major breakthrough in complexity theory. Question: Where can the complexity classes RP, BPP, PP, BQP, MA, and PH be located?
answer:
between P and PSPACE


question:
Passage: A variety of alternatives to the Y. pestis have been put forward. Twigg suggested that the cause was a form of anthrax, and Norman Cantor (2001) thought it may have been a combination of anthrax and other pandemics. Scott and Duncan have argued that the pandemic was a form of infectious disease that characterise as hemorrhagic plague similar to Ebola. Archaeologist Barney Sloane has argued that there is insufficient evidence of the extinction of a large number of rats in the archaeological record of the medieval waterfront in London and that the plague spread too quickly to support the thesis that the Y. pestis was spread from fleas on rats; he argues that transmission must have been person to person. However, no single alternative solution has achieved widespread acceptance. Many scholars arguing for the Y. pestis as the major agent of the pandemic suggest that its extent and symptoms can be explained by a combination of bubonic plague with other diseases, including typhus, smallpox and respiratory infections. In addition to the bubonic infection, others point to additional septicemic (a type of 'blood poisoning') and pneumonic (an airborne plague that attacks the lungs before the rest of the body) forms of the plague, which lengthen the duration of outbreaks throughout the seasons and help account for its high mortality rate and additional recorded symptoms. In 2014, scientists with Public Health England announced the results of an examination of 25 bodies exhumed from the Clerkenwell area of London, as well as of wills registered in London during the period, which supported the pneumonic hypothesis. Question: What was Norman Cantor's theory about the plague?
answer:
a combination of anthrax and other pandemics


question:
Passage: The city is served by the Tyne and Wear Metro, a system of suburban and underground railways covering much of Tyne and Wear. It was opened in five phases between 1980 and 1984, and was Britain's first urban light rail transit system; two extensions were opened in 1991 and 2002. It was developed from a combination of existing and newly built tracks and stations, with deep-level tunnels constructed through Newcastle city centre. A bridge was built across the Tyne, between Newcastle and Gateshead, and opened by Queen Elizabeth II in 1981. The network is operated by DB Regio on behalf of Nexus and carries over 37 million passengers a year, extending as far as Newcastle Airport, Tynemouth, South Shields and South Hylton in Sunderland. In 2004, the company Marconi designed and constructed the mobile radio system to the underground Metro system. The Metro system was the first in the UK to have mobile phone antennae installed in the tunnels. Question: What underground railways cover much of Tyne and Wear?
answer:
the Tyne and Wear Metro