Which sentence needs a comma??
(1)The soapbox derby is an enduring American tradition, one in long-standing. (2) Building cars on their own, with supplies they have chosen and purchased, is something many drivers take great pride in. (3) The sport is not without its hazards, but these hazards pale by comparison with other sports. (4) What is also impressive about the sport is the amount of knowledge care, and patience it takes to participate.