Problem: LED lamps have been advocated as the newest and best environmental lighting method. According to the Energy Saving Trust, LED lamps use only 10% power compared to a standard incandescent bulb, where compact fluorescent lamps use 20% and energy saving halogen lamps 70%. The lifetime is also much longer up to 50,000 hours. A downside is still the initial cost, which is higher than that of compact fluorescent lamps.
What is the average lifetime of a CFL?
The answer is the following: 50,000 hours

Problem: The competition is open to any eligible club down to Levels 10 of the English football league system - all 92 professional clubs in the Premier League and Football League (Levels 1 to 4), and several hundred "non-league" teams in Steps 1 to 6 of the National League System (Levels 5 to 10). A record 763 clubs competed in 201112. The tournament consists of 12 randomly drawn rounds followed by the semi-finals and the final. Entrants are not seeded, although a system of byes based on league level ensures higher ranked teams enter in later rounds - the minimum number of games needed to win the competition ranges from six to fourteen.
Who is the competition open too?
The answer is the following: any eligible club

Problem: Lee and Guenther have rejected most of the arguments put forward by Wilmsen. Doron Shultziner and others have argued that we can learn a lot about the life-styles of prehistoric hunter-gatherers from studies of contemporary hunter-gatherersespecially their impressive levels of egalitarianism.
Who has offered arguments that Lee and Guenther disliked?
The answer is the following: Wilmsen

Problem: Major reductions in the cost of lighting occurred with the discovery of whale oil and kerosene. Gas lighting was economical enough to power street lights in major cities starting in the early 1800s, and was also used in some commercial buildings and in the homes of wealthy people. The gas mantle boosted the luminosity of utility lighting and of kerosene lanterns. The next major drop in price came about with the incandescent light bulb powered by electricity.
When did gas powered street lights became economically available.
The answer is the following:
early 1800s