Article: Color in glass may be obtained by addition of electrically charged ions (or color centers) that are homogeneously distributed, and by precipitation of finely dispersed particles (such as in photochromic glasses). Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron(II) oxide (FeO) impurities of up to 0.1 wt% produce a green tint, which can be viewed in thick pieces or with the aid of scientific instruments. Further FeO and Cr2O3 additions may be used for the production of green bottles. Sulfur, together with carbon and iron salts, is used to form iron polysulfides and produce amber glass ranging from yellowish to almost black. A glass melt can also acquire an amber color from a reducing combustion atmosphere. Manganese dioxide can be added in small amounts to remove the green tint given by iron(II) oxide. When used in art glass or studio glass is colored using closely guarded recipes that involve specific combinations of metal oxides, melting temperatures and 'cook' times. Most colored glass used in the art market is manufactured in volume by vendors who serve this market although there are some glassmakers with the ability to make their own color from raw materials.

Question: What can prevent a green color in glass?
Ans: Manganese dioxide

Article: Asthma is thought to be caused by a combination of genetic and environmental factors. Environmental factors include exposure to air pollution and allergens. Other potential triggers include medications such as aspirin and beta blockers. Diagnosis is usually based on the pattern of symptoms, response to therapy over time, and spirometry. Asthma is classified according to the frequency of symptoms, forced expiratory volume in one second (FEV1), and peak expiratory flow rate. It may also be classified as atopic or non-atopic where atopy refers to a predisposition toward developing a type 1 hypersensitivity reaction.

Question: What patterns are used to diagnose asthma?
Ans: the pattern of symptoms, response to therapy over time, and spirometry

Article: These styles generally have either two f-shaped soundholes like a violin (F-5 and A-5), or an oval sound hole (F-4 and A-4 and lower models) directly under the strings. Much variation exists between makers working from these archetypes, and other variants have become increasingly common. Generally, in the United States, Gibson F-hole F-5 mandolins and mandolins influenced by that design are strongly associated with bluegrass, while the A-style is associated other types of music, although it too is most often used for and associated with bluegrass. The F-5's more complicated woodwork also translates into a more expensive instrument.

Question: Why is the F-5 mandolin more expensive?
Ans: complicated woodwork

Article: In matches with multiple competitors, an elimination system may be used. Any wrestler who has a fall scored against them is forced out of the match, and the match continues until only one remains. However, it is much more common when more than two wrestlers are involved to simply go one fall, with the one scoring the fall, regardless of who they scored it against, being the winner. In championship matches, this means that, unlike one-on-one matches (where the champion can simply disqualify themselves or get themselves counted out to retain the title via the "champion's advantag"), the champion does not have to be pinned or involved in the decision to lose the championship. However, heel champions often find advantages, not in champion's advantage, but in the use of weapons and outside interference, as these poly-sided matches tend to involve no holds barred rules.

Question: What usually happens when two or more wrestlers are involved?
Ans:
to simply go one fall, with the one scoring the fall, regardless of who they scored it against, being the winner.