QUES: 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.

Why are no leeches endangered?
What is the answer?
ANS: unanswerable
QUES: The Great Plains is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. This area covers parts, but not all, of the states of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming, and the Canadian provinces of Alberta, Manitoba and Saskatchewan. The region is known for supporting extensive cattle ranching and dry farming.

What lies south of the Great Plains?
What is the answer?
ANS: unanswerable
QUES: The graphic novelbook-length comicsbegan to gain attention after Will Eisner popularized the term with his book A Contract with God (1978). The term became widely known with the public after the commercial success of Maus, Watchmen, and The Dark Knight Returns in the mid-1980s. In the 21st century graphic novels became established in mainstream bookstores and libraries and webcomics became common.

The loss in popularity of the Watchmen, The Dark Knight Returns and what other comic helped popularize "graphic novel" as a term?
What is the answer?
ANS:
unanswerable