Progressions, or using progressions, is teaching skills in an order that the skills build upon each other. An example is teaching an extension, pop cradle before basket tosses because the motion of bases starting in the athletic stance, exploding through their legs, and taking to top person to an extended position is similar to the motion of tossing a basket. For the top person the motion of loading in, holding their weight, standing up, and locking out are similar to a basket.
Rules in Cheerleading are the restrictions placed on teams. Levels are different versions of the rules and restrictions implemented to give athletes of varying skill restrictions more appropriate for their ability. The levels used in cheerleading are progressive, meaning Level 2 is more advanced than Level 1, Level 5 permits more than Level 4, and so on.
Progressions should be taught regardless of level or whether or not levels exist. Progressions were used before levels were implemented and would continue to be used by good coaches if Levels were removed or adjusted.