Problem: Tucson's Sun Tran bus system serves greater Tucson with standard, express, regional shuttle, and on-demand shuttle bus service. It was awarded Best Transit System in 1988 and 2005. A 3.9-mile streetcar line, Sun Link, connects the University of Arizona campus with 4th Avenue, downtown, and the Mercado District west of Interstate 10 and the Santa Cruz River. Ten-minute headway passenger service began July 25, 2014. The streetcar utilizes Sun Tran's card payment and transfer system, connecting with the University of Arizona's CatTran shuttles, Amtrak, and Greyhound intercity bus service.
How long is the Sun Link?
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Answer: 3.9-mile

Problem: Families and households were still largely independent economically, and the household was probably the center of life. However, excavations in Central Europe have revealed that early Neolithic Linear Ceramic cultures ("Linearbandkeramik") were building large arrangements of circular ditches between 4800 BC and 4600 BC. These structures (and their later counterparts such as causewayed enclosures, burial mounds, and henge) required considerable time and labour to construct, which suggests that some influential individuals were able to organise and direct human labour though non-hierarchical and voluntary work remain possibilities.
What features about the individuals suggests that it was built by people under a leader's command?
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Answer: unanswerable

Problem: In 1982, the US Mint began minting pennies coated in copper but made primarily of zinc. With the new zinc pennies, there is the potential for zinc toxicosis, which can be fatal. One reported case of chronic ingestion of 425 pennies (over 1 kg of zinc) resulted in death due to gastrointestinal bacterial and fungal sepsis, whereas another patient, who ingested 12 grams of zinc, only showed lethargy and ataxia (gross lack of coordination of muscle movements). Several other cases have been reported of humans suffering zinc intoxication by the ingestion of zinc coins.
Why have people reported zinc intoxication?
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Answer:
ingestion of zinc coins