Problem: Time:

Time has historically been closely related with space, the two together merging into spacetime in Einstein's special relativity and general relativity. According to these theories, the concept of time depends on the spatial reference frame of the observer, and the human perception as well as the measurement by instruments such as clocks are different for observers in relative motion. For example, if a spaceship carrying a clock flies through space at (very nearly) the speed of light, its crew does not notice a change in the speed of time on board their vessel because everything traveling at the same speed slows down at the same rate (including the clock, the crew's thought processes, and the functions of their bodies). However, to a stationary observer watching the spaceship fly by, the spaceship appears flattened in the direction it is traveling and the clock on board the spaceship appears to move very slowly.

What does a space crew's thought processes depend on?
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A: unanswerable

Problem: Conversely, most heat-treatable alloys are precipitation hardening alloys, which produce the opposite effects that steel does. When heated to form a solution and then cooled quickly, these alloys become much softer than normal, during the diffusionless transformation, and then harden as they age. The solutes in these alloys will precipitate over time, forming intermetallic phases, which are difficult to discern from the base metal. Unlike steel, in which the solid solution separates to form different crystal phases, precipitation hardening alloys separate to form different phases within the same crystal. These intermetallic alloys appear homogeneous in crystal structure, but tend to behave heterogeneous, becoming hard and somewhat brittle.
What do precipitation hardening alloys behave similarly to?
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Answer: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Over 50% of undergraduate students live on campus. Most of the residence halls on campus are located on the South 40, named because of its adjacent location on the south side of the Danforth Campus and its size of 40 acres (160,000 m2). It is the location of all the freshman buildings as well as several upperclassman buildings, which are set up in the traditional residential college system. All of the residential halls are co-ed. The South 40 is organized as a pedestrian-friendly environment wherein residences surround a central recreational lawn known as the Swamp. Bear's Den (the largest dining hall on campus), the Habif Health and Wellness Center (Student Health Services), the Residential Life Office, University Police Headquarters, various student-owned businesses (e.g. the laundry service, Wash U Wash), and the baseball, softball, and intramural fields are also located on the South 40.
What percent of undergraduate students live on campus at Washington University?
A: Over 50%

Context and question: Another significant issue unique to LaserDisc is one involving the inconsistency of playback quality between different makers and models of player. On most televisions, a given DVD player will produce a picture that is visually indistinguishable from other units. Differences in image quality between players only becomes easily apparent on large televisions and substantial leaps in image quality are generally only obtained with expensive, high-end players that allow for post-processing of the MPEG-2 stream during playback. In contrast, LaserDisc playback quality is highly dependent on hardware quality. Major variances in picture quality appear between different makers and models of LD players, even when tested on a low to mid-range television. The obvious benefits of using high quality equipment has helped keep demand for some players high, thus also keeping pricing for those units comparably high. In the 1990s, notable players sold for anywhere from US$200 to well over $1,000, while older and less desirable players could be purchased in working condition for as little as $25.
What range of prices were high-end LaserDisc players in the 1990s?
Answer: US$200 to well over $1,000

Question: BYU alumni in academia include former Dean of the Harvard Business School Kim B. Clark, two time world's most influential business thinker Clayton M. Christensen, Michael K. Young '73, current president of the University of Washington, Matthew S. Holland, current president of Utah Valley University, Stan L. Albrecht, current president of Utah State University, Teppo Felin, Professor at the University of Oxford, and Stephen D. Nadauld, previous president of Dixie State University. The University also graduated Nobel Prize winner Paul D. Boyer, as well as Philo Farnsworth (inventor of the electronic television) and Harvey Fletcher (inventor of the hearing aid). Four of BYU's thirteen presidents were alumni of the University. Additionally, alumni of BYU who have served as business leaders include Citigroup CFO Gary Crittenden '76, former Dell CEO Kevin Rollins '84, Deseret Book CEO Sheri L. Dew, and Matthew K. McCauley, CEO of children's clothing company Gymboree.
Is there an answer to this question: Which Nobel Prize winner graduated from BYU?

Answer: Paul D. Boyer

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The Sahara is the world's largest low-latitude hot desert. The area is located in the horse latitudes under the subtropical ridge, a significant belt of semi-permanent subtropical warm-core high pressure where the air from upper levels of the troposphere tends to sink towards the ground. This steady descending airflow causes a warming and a drying effect in the upper troposphere. The sinking air prevents evaporating water from rising and, therefore, prevents the adiabatic cooling, which makes cloud formation extremely difficult to nearly impossible.
What makes it difficult for clouds to form?
A:
sinking air