Scrapheap Challenge and a month to build a vehicle to compete in a varied set of trials, such as auto "bowling", a race through a flooded course, a "car coaster", car "sumo" and other tests. The winners were the Aquaholics from the UK. Hosted by Cathy Rogers and Henry Rollins, it lasted one season. Another spin-off series was instituted from 2004 to 2006 and was broadcast following the main series. It was also presented by Robert Llewellyn and Lisa Rogers. It involved several teams being allocated a budget and several weeks to construct a road-legal vehicle which, if classified as a car,
Challenge hypothesis However, during periods of heightened male aggression, testosterone levels increase further to a maximum physiological level. This additional boost in testosterone appears to facilitate male-male aggression, particularly during territory formation and mate guarding, and is also characterized by a lack of paternal care. The challenge hypothesis has come to explain patterns of testosterone production as predictive of aggression across more than 60 species. The challenge hypothesis presents a three-level model at which testosterone may be present in circulation. The first level (Level A) represents the baseline level of testosterone during the non-breeding season. Level A is presumed to maintain feedback