Problem: Karl Popper:

In response to a given problem situation (), a number of competing conjectures, or tentative theories (), are systematically subjected to the most rigorous attempts at falsification possible. This process, error elimination (), performs a similar function for science that natural selection performs for biological evolution. Theories that better survive the process of refutation are not more true, but rather, more "fit"in other words, more applicable to the problem situation at hand (). Consequently, just as a species' biological fitness does not ensure continued survival, neither does rigorous testing protect a scientific theory from refutation in the future. Yet, as it appears that the engine of biological evolution has, over many generations, produced adaptive traits equipped to deal with more and more complex problems of survival, likewise, the evolution of theories through the scientific method may, in Popper's view, reflect a certain type of progress: toward more and more interesting problems (). For Popper, it is in the interplay between the tentative theories (conjectures) and error elimination (refutation) that scientific knowledge advances toward greater and greater problems; in a process very much akin to the interplay between genetic variation and natural selection.

What serves a different purpose in biological evolution than error elimination serves in science?
---
A: unanswerable

Problem: The spectrum emitted by a blackbody radiator at temperatures of incandescent bulbs does not match the sensitivity characteristics of the human eye; the light emitted does not appear white, and most is not in the range of wavelengths at which the eye is most sensitive. Tungsten filaments radiate mostly infrared radiation at temperatures where they remain solid below 3,695 K (3,422 C; 6,191 F). Donald L. Klipstein explains it this way: "An ideal thermal radiator produces visible light most efficiently at temperatures around 6,300 C (6,600 K; 11,400 F). Even at this high temperature, a lot of the radiation is either infrared or ultraviolet, and the theoretical luminous efficacy (LER) is 95 lumens per watt." No known material can be used as a filament at this ideal temperature, which is hotter than the sun's surface. An upper limit for incandescent lamp luminous efficacy (LER) is around 52 lumens per watt, the theoretical value emitted by tungsten at its melting point.
What is the theoretical LER value of tungsten at its melting point?
---
Answer: 52 lumens per watt

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Besides lossy compression methods, lossless formats are a significant alternative to MP3 because they provide unaltered audio content, though with an increased file size compared to lossy compression. Lossless formats include FLAC (Free Lossless Audio Codec), Apple Lossless and many others.
What is another example of a lossless format other than Apple Lossless?
A: FLAC

Context and question: Miami is the southern terminus of Amtrak's Atlantic Coast services, running two lines, the Silver Meteor and the Silver Star, both terminating in New York City. The Miami Amtrak Station is located in the suburb of Hialeah near the Tri-Rail/Metrorail Station on NW 79 St and NW 38 Ave. Current construction of the Miami Central Station will move all Amtrak operations from its current out-of-the-way location to a centralized location with Metrorail, MIA Mover, Tri-Rail, Miami International Airport, and the Miami Intermodal Center all within the same station closer to Downtown. The station was expected to be completed by 2012, but experienced several delays and was later expected to be completed in late 2014, again pushed back to early 2015.
After the first delay, in what year was the Miami Central Station supposed to close?
Answer: unanswerable

Question: Mary resided in "her own house"[Lk.1:56] in Nazareth in Galilee, possibly with her parents, and during her betrothal the first stage of a Jewish marriage the angel Gabriel announced to her that she was to be the mother of the promised Messiah by conceiving him through the Holy Spirit, and she responded, "I am the handmaid of the Lord. Let it be done unto me according to your word." After a number of months, when Joseph was told of her conception in a dream by "an angel of the Lord", he planned to divorce her; but the angel told him to not hesitate to take her as his wife, which Joseph did, thereby formally completing the wedding rites.[Mt 1:18-25]
Is there an answer to this question: In his dream, who told Joseph about Mary's conception?

Answer: an angel of the Lord

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The majority of the world's airports are non-towered, with no air traffic control presence. However, at particularly busy airports, or airports with other special requirements, there is an air traffic control (ATC) system whereby controllers (usually ground-based) direct aircraft movements via radio or other communications links. This coordinated oversight facilitates safety and speed in complex operations where traffic moves in all three dimensions. Air traffic control responsibilities at airports are usually divided into at least two main areas: ground and tower, though a single controller may work both stations. The busiest airports also have clearance delivery, apron control, and other specialized ATC stations.
What does a clearance delivery system do at an airport?
A:
unanswerable