What are some causes leading into the decline of the roman republic

Invasions by Barbarian tribes

The most straightforward theory for Western Rome's collapse pins the fall on a string of military losses sustained against outside forces. Rome had tangled with Germanic tribes for centuries, but by the 300s “barbarian” groups like the Goths had encroached beyond the Empire's borders.

answer; biological;

answer; exaggerate what you believe is the deception and state it, hoping that the other will jump in to "correct" the statement;