Short answers, pulled from the story.
Paul Tutmarc created the Model 736 Bass Fiddle which appeared in Audiovox sales catalogs around 1935. This instrument featured four strings and a single pickup mounted beneath them while lying flat across the player's lap.
Leo Fender and George Fullton began building the Precision Bass in October 1951 with simple slab bodies without any edge contours. By 1957 the design evolved to include beveled edges for comfort and replaced the original single unit with a split coil pickup.
The Jazz Bass entered the market in 1960 with an offset waist body shape that improved comfort for seated players compared to previous flat models. It utilized two single-coil pickups to give the instrument a distinct tonal character.
Music Man introduced the StingRay in 1974 which made active electronics common starting that same year. These powered systems included preamplifiers and knobs for boosting or cutting frequencies to allow precise sound shaping.
Anthony Jackson commissioned Carl Thompson to build a six-string bass in 1975 that added low B and high C strings to standard tuning. This custom instrument featured scale lengths varying from thirty inches up to thirty-five inches depending on manufacturer choices.