Principle of Reversibility is the decline of skill and fitness level due to taking a break from exercise or being inactive.
It is called such because all the result of hardwork and labor done to achieve and maintain one's skill and fitness level will be reversed because said fitness regime is not maintained; making the body lax, eventually declining in skill performance and fitness level.
I would recommend studying and then looking it up
Pick the one with less trans fat, more fiber, and the least sugar. Seeing the phrase "100%" on the packaging usually means whole grains, which can be good as well.
