The arrangement of plot events in a tragedy reveals
the desires of the audience
the triumph of the tragic hero
the humor of the playwright
the downfall of the protagonist

The arrangement of plot events in a tragedy reveals the downfall of the protagonist.

Explanation:

The plot of a story has to do with the sequence of events that are present in a narrative. Tragedies tell the story of a tragic hero, the latter never gets a happy ending. The tragic hero is usually a very honorable person who has a very good reputation, however, he has this tragic flaw that makes him start his downfall until there is no possible way back. In tragedies, there is a lot of death, and the protagonist (the tragic hero) dies because of his flaw. In Hamlet, for example, only one character survives, the one that tells the story.

Moreover, consider,  the tragedy of Macbeth, his ambition is his tragic flaw, and it is because of his ambition that he will end up dying.

The structure that a tragedy has is the follwing:

EXPOSITION (this is usually act 1 in a play - main characters and topics are introduced)

RISING ACTION (usually act 2, more characters are introduced, the story is further developed)

CLIMAX (act 3,This is the peak of action of the story, as from this moment the downfall of the tragic hero begins)

FALLING ACTION (act 4, the downfall continues, more characters die)

RESOLUTION/RESTORATION OF ORDER (act 5, the tragic hero dies, order is restored)