Input: Read this: Earthworms are Oligochaetes that support terrestrial food chains both as prey and in some regions are important in aeration and enriching of soil. The burrowing of marine polychaetes, which may constitute up to a third of all species in near-shore environments, encourages the development of ecosystems by enabling water and oxygen to penetrate the sea floor. In addition to improving soil fertility, annelids serve humans as food and as bait. Scientists observe annelids to monitor the quality of marine and fresh water. Although blood-letting is no longer in favor with doctors, some leech species are regarded as endangered species because they have been over-harvested for this purpose in the last few centuries. Ragworms' jaws are now being studied by engineers as they offer an exceptional combination of lightness and strength.
Question: Why are some leeches endangered?

Output: they have been over-harvested


Input: Read this: Ancient and medieval Hindu texts identify six pramāṇas as correct means of accurate knowledge and truths: pratyakṣa (perception), anumāṇa (inference), upamāṇa (comparison and analogy), arthāpatti (postulation, derivation from circumstances), anupalabdi (non-perception, negative/cognitive proof) and śabda (word, testimony of past or present reliable experts) Each of these are further categorized in terms of conditionality, completeness, confidence and possibility of error, by each school . The various schools vary on how many of these six are valid paths of knowledge. For example, the Cārvāka nāstika philosophy holds that only one (perception) is an epistemically reliable means of knowledge, the Samkhya school holds three are (perception, inference and testimony), while the Mīmāṃsā and Advaita schools hold all six are epistemically useful and reliable means to knowledge.
Question: What do ancient Hindu writings identify as the means to knowledge and truth?

Output: pramāṇas


Input: Read this: Some organisms, such as the lichen Trapelia involuta or microorganisms such as the bacterium Citrobacter, can absorb concentrations of uranium that are up to 300 times the level of their environment. Citrobacter species absorb uranyl ions when given glycerol phosphate (or other similar organic phosphates). After one day, one gram of bacteria can encrust themselves with nine grams of uranyl phosphate crystals; this creates the possibility that these organisms could be used in bioremediation to decontaminate uranium-polluted water. The proteobacterium Geobacter has also been shown to bioremediate uranium in ground water. The mycorrhizal fungus Glomus intraradices increases uranium content in the roots of its symbiotic plant.
Question: What fungus is known to cause uranium content in its symbiotic plant roots to decrease?

Output: unanswerable


Input: Read this: Prior to the emergence of Kievan Rus' in the 9th century AD, the lands between the Baltic Sea and Black Sea were primarily populated by eastern Slavic tribes. In the northern region around Novgorod were the Ilmen Slavs and neighboring Krivichi, who occupied territories surrounding the headwaters of the West Dvina, Dnieper, and Volga Rivers. To their north, in the Ladoga and Karelia regions, were the Finnic Chud tribe. In the south, in the area around Kiev, were the Poliane, a group of Slavicized tribes with Iranian origins, the Drevliane to the west of the Dnieper, and the Severiane to the east. To their north and east were the Vyatichi, and to their south was forested land settled by Slav farmers, giving way to steppelands populated by nomadic herdsmen.
Question: Which tribe resided in the southeast?

Output:
unanswerable