Scrapheap Challenge events. Examples of challenges included making a jet car, a bridging machine, a car-crusher, and a machine to fling a British Leyland Mini as far as possible. Assistant producer Eve Kay had the idea for the show after watching a scene in the movie "Apollo 13", where NASA engineers had only a short period of time to construct a carbon dioxide filter out of parts available on the space capsule. The show also draws its inspiration from the 1980s TV series "The Great Egg Race". The UK show was originally presented by Robert Llewellyn, joined in series 2-4 by producer
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