Question: For a century, the Appalachians were a barrier to the westward expansion of the British colonies. The continuity of the mountain system, the bewildering multiplicity of its succeeding ridges, the tortuous courses and roughness of its transverse passes, a heavy forest, and dense undergrowth all conspired to hold the settlers on the seaward-sloping plateaus and coastal plains. Only by way of the Hudson and Mohawk Valleys, Cumberland Gap, the Wachesa Trail,[undue weight? – discuss] and round about the southern termination of the system were there easy routes to the interior of the country, and these were long closed by powerful Native American tribes such as the Iroquois, Creek, and Cherokee, among others. Expansion was also blocked by the alliances the British Empire had forged with Native American tribes, the proximity of the Spanish colonies in the south and French activity throughout the interior.
Try to answer this question if possible: What were the name of the French tribes?
Answer: unanswerable
Question: Many energy markets, institutions, and policies have been developed to support the production and use of fossil fuels. Newer and cleaner technologies may offer social and environmental benefits, but utility operators often reject renewable resources because they are trained to think only in terms of big, conventional power plants. Consumers often ignore renewable power systems because they are not given accurate price signals about electricity consumption. Intentional market distortions (such as subsidies), and unintentional market distortions (such as split incentives) may work against renewables. Benjamin K. Sovacool has argued that "some of the most surreptitious, yet powerful, impediments facing renewable energy and energy efficiency in the United States are more about culture and institutions than engineering and science".
Try to answer this question if possible:  Why do utility operators only ever accept renewable resources?
Answer: unanswerable
Question: Lossless data compression algorithms usually exploit statistical redundancy to represent data without losing any information, so that the process is reversible. Lossless compression is possible because most real-world data exhibits statistical redundancy. For example, an image may have areas of colour that do not change over several pixels; instead of coding "red pixel, red pixel, ..." the data may be encoded as "279 red pixels". This is a basic example of run-length encoding; there are many schemes to reduce file size by eliminating redundancy.
Try to answer this question if possible: What may have colors that do not change over several pixels?
Answer: an image
Question: In March 2005, the Security Council formally referred the situation in Darfur to the Prosecutor of the International Criminal Court, taking into account the Commission report but without mentioning any specific crimes. Two permanent members of the Security Council, the United States and China, abstained from the vote on the referral resolution. As of his fourth report to the Security Council, the Prosecutor has found "reasonable grounds to believe that the individuals identified [in the UN Security Council Resolution 1593] have committed crimes against humanity and war crimes," but did not find sufficient evidence to prosecute for genocide.
Try to answer this question if possible: When did the Security Council formally refer the situation in Darfur to China?
Answer:
unanswerable