It has been five years since you've taken a psychology course and you find yourself back in school taking introduction to psychology all over again. unfortunately, you're having a difficult time remembering anything that you learned previously. your forgetting in this situation is most likely due to

I believe the answer is: Decay.
In psychological term, decay refers to the process where memory started to faded over time if it's not constantly retreived
The main cause of such process is the deterioration of brain cells that common to happen as we got older.

Iam a german monk and professor of theology. i believe that the catholic church's practice of buying forgiveness of sins through indulgences is wrong. i have translated the bible into german to make it easier for more people to be able to study it. i am here to stand by my writings and i refuse your demand that i recant them