Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Hunter-gatherer societies manifest significant variability, depending on climate zone/life zone, available technology and societal structure. Archaeologists examine hunter-gatherer tool kits to measure variability across different groups. Collard et al. (2005) found temperature to be the only statistically significant factor to impact hunter-gatherer tool kits. Using temperature as a proxy for risk, Collard et al.'s results suggest that environments with extreme temperatures pose a threat to hunter-gatherer systems significant enough to warrant increased variability of tools. These results support Torrence's (1989) theory that risk of failure is indeed the most important factor in determining the structure of hunter-gatherer toolkits.
What is the threat that extreme temperature causes in environment?
A: significant

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Present-day Christian religious bodies known for conducting their worship services without musical accompaniment include some Presbyterian churches devoted to the regulative principle of worship, Old Regular Baptists, Primitive Baptists, Plymouth Brethren, Churches of Christ, the Old German Baptist Brethren, Doukhobors the Byzantine Rite and the Amish, Old Order Mennonites and Conservative Mennonites. Certain high church services and other musical events in liturgical churches (such as the Roman Catholic Mass and the Lutheran Divine Service) may be a cappella, a practice remaining from apostolic times. Many Mennonites also conduct some or all of their services without instruments. Sacred Harp, a type of folk music, is an a cappella style of religious singing with shape notes, usually sung at singing conventions.
What are some present day Christian churces nolonger use the a capella form?
A: unanswerable

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In addition to the sports he played at Yale, Kerry is described by Sports Illustrated, among others, as an "avid cyclist", primarily riding on a road bike. Prior to his presidential bid, Kerry was known to have participated in several long-distance rides (centuries). Even during his many campaigns, he was reported to have visited bicycle stores in both his home state and elsewhere. His staff requested recumbent stationary bikes for his hotel rooms. He has also been a snowboarder, windsurfer, and sailor.
What are 'centuries' in bicycling?
A: long-distance rides

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Initially the existing 5:3 aspect ratio had been the main candidate but, due to the influence of widescreen cinema, the aspect ratio 16:9 (1.78) eventually emerged as being a reasonable compromise between 5:3 (1.67) and the common 1.85 widescreen cinema format. An aspect ratio of 16:9 was duly agreed upon at the first meeting of the IWP11/6 working party at the BBC's Research and Development establishment in Kingswood Warren. The resulting ITU-R Recommendation ITU-R BT.709-2 ("Rec. 709") includes the 16:9 aspect ratio, a specified colorimetry, and the scan modes 1080i (1,080 actively interlaced lines of resolution) and 1080p (1,080 progressively scanned lines). The British Freeview HD trials used MBAFF, which contains both progressive and interlaced content in the same encoding.
Which encoding contains both not progressive and interlaced content?
A:
unanswerable