Garret is frustrated and angry when his request for a pay raise is turned down. after work, garret goes to his gym and hits the punching bag for 10 minutes. garret finds that he feels less tense and wound up after his workout. this change in garret's mood is consistent with the concept of

The correct answer is catharsis.

Catharsis refers to a technique people use in order to release and cope with negative feelings or emotions. Catharsis basically means releasing emotions. When Garret feels better after hitting a punching bag for 10 minutes after getting frustrated and angry when his request for a pay raise is turned down, hitting the punching bag is  a catharsis since it helps Garret release his negative emotions and frustrations. 

Both the han and the roman empire decline as a result of social unrest during their collapse.