a.骑:骑自行车(ride bicycle), 骑马 (ride horse)骑摩托(ride motor)
b.in order to understand “坐” maybe to figure out its relationship with "座” will help you 坐:v. sit or take a seat on a vehicle 座:n. seat
c.乘坐: formal degree 乘坐>乘>坐 "乘" sounds like more elegant.
People don't use "乘坐” in daliy communitcation.
(Sub way, air plane, bus)Operating Company will use it in broadcast to show its
respect and profession to customers.
“乘” and "坐“ are similar. but according to its syllable,i would like to use"坐 zuo"
because it is shorter than "乘 cheng". :)