Article: Britain's first use of brass occurred around the 3rd–2nd century BC. In North America, copper mining began with marginal workings by Native Americans. Native copper is known to have been extracted from sites on Isle Royale with primitive stone tools between 800 and 1600. Copper metallurgy was flourishing in South America, particularly in Peru around 1000 AD; it proceeded at a much slower rate on other continents. Copper burial ornamentals from the 15th century have been uncovered, but the metal's commercial production did not start until the early 20th century.

Question: When did commercial production of copper begin?
Ans: early 20th century


Article: Proponents of affirmative action recognize that the policy is inherently unequal; however, minding the inescapable fact that historic inequalities exist in America, they believe the policy is much more fair than one in which these circumstances are not taken into account. Furthermore, those in favor of affirmative action see it as an effort towards inclusion rather than a discriminatory practice. "Job discrimination is grounded in prejudice and exclusion, whereas affirmative action is an effort to overcome prejudicial treatment through inclusion. The most effective way to cure society of exclusionary practices is to make special efforts at inclusion, which is exactly what affirmative action does."

Question: What is one of the issues with affirmative action?
Ans: inherently unequal


Article: Special guest referees may be used from time to time; by virtue of their celebrity status, they are often scripted to dispense with the appearance of neutrality and use their influence to unfairly influence the outcome of the match for added dramatic impact. Face special referees will often fight back against hostile heel wrestlers, particularly if the special referee is either a wrestler themselves or a famous martial artist (such as Tito Ortiz in the main event at TNA's THard Justice in 2005). They also have the power to eject from ringside any of the heel wrestler's entourage/stable, who may otherwise interfere with the match.

Question: What are famous referees directed to do?
Ans: often scripted to dispense with the appearance of neutrality and use their influence to unfairly influence the outcome of the match for added dramatic impact. F


Article: Solar chemical processes use solar energy to drive chemical reactions. These processes offset energy that would otherwise come from a fossil fuel source and can also convert solar energy into storable and transportable fuels. Solar induced chemical reactions can be divided into thermochemical or photochemical. A variety of fuels can be produced by artificial photosynthesis. The multielectron catalytic chemistry involved in making carbon-based fuels (such as methanol) from reduction of carbon dioxide is challenging; a feasible alternative is hydrogen production from protons, though use of water as the source of electrons (as plants do) requires mastering the multielectron oxidation of two water molecules to molecular oxygen. Some have envisaged working solar fuel plants in coastal metropolitan areas by 2050 –  the splitting of sea water providing hydrogen to be run through adjacent fuel-cell electric power plants and the pure water by-product going directly into the municipal water system. Another vision involves all human structures covering the earth's surface (i.e., roads, vehicles and buildings) doing photosynthesis more efficiently than plants.

Question: What is a possible alternative to making carbon-based fuels from reduction of carbon dioxide?
Ans:
hydrogen production from protons