Problem: Please answer a question about the following article about Circadian rhythm:
Early research into circadian rhythms suggested that most people preferred a day closer to 25 hours when isolated from external stimuli like daylight and timekeeping. However, this research was faulty because it failed to shield the participants from artificial light. Although subjects were shielded from time cues (like clocks) and daylight, the researchers were not aware of the phase-delaying effects of indoor electric lights.[dubious – discuss] The subjects were allowed to turn on light when they were awake and to turn it off when they wanted to sleep. Electric light in the evening delayed their circadian phase.[citation needed] A more stringent study conducted in 1999 by Harvard University estimated the natural human rhythm to be closer to 24 hours, 11 minutes: much closer to the solar day but still not perfectly in sync.
When did more stringent testing determine that humans preferred a 24 hour day? 
A: 1999
Problem: Please answer a question about the following article about Old English:
Unlike Modern English, Old English is a language rich in morphological diversity. It maintains several distinct cases: the nominative, accusative, genitive, dative and (vestigially) instrumental. The only remnants of this system in Modern English are in the forms of a few pronouns (such as I/me/mine, she/her, who/whom/whose) and in the possessive ending -'s, which derives from the old (masculine and neuter) genitive ending -es. In Old English, however, nouns and their modifying words take appropriate endings depending on their case.
In Old English, noun endings vary on what basis?
A: their case
Problem: Please answer a question about the following article about Group (mathematics):
Groups are also applied in many other mathematical areas. Mathematical objects are often examined by associating groups to them and studying the properties of the corresponding groups. For example, Henri Poincaré founded what is now called algebraic topology by introducing the fundamental group. By means of this connection, topological properties such as proximity and continuity translate into properties of groups.i[›] For example, elements of the fundamental group are represented by loops. The second image at the right shows some loops in a plane minus a point. The blue loop is considered null-homotopic (and thus irrelevant), because it can be continuously shrunk to a point. The presence of the hole prevents the orange loop from being shrunk to a point. The fundamental group of the plane with a point deleted turns out to be infinite cyclic, generated by the orange loop (or any other loop winding once around the hole). This way, the fundamental group detects the hole.
What did Henri Poincaré introduce when he established algebraic topology?
A: the fundamental group
Problem: Please answer a question about the following article about Karl Popper:
The creation–evolution controversy in the United States raises the issue of whether creationistic ideas may be legitimately called science and whether evolution itself may be legitimately called science. In the debate, both sides and even courts in their decisions have frequently invoked Popper's criterion of falsifiability (see Daubert standard). In this context, passages written by Popper are frequently quoted in which he speaks about such issues himself. For example, he famously stated "Darwinism is not a testable scientific theory, but a metaphysical research program—a possible framework for testable scientific theories." He continued:
Popper's philosophy is often applied in what political debate concerning biological science?
A:
creation–evolution