To construct a timeline of significant events that led to the formation of the Roman Empire in chronological order, the correct order would be:
- Gracchi brothers’ assassinations (133-121 BC)
- Sulla’s march on Rome (88 BC)
- First Triumvirate (60-53 BC)
- March across the Rubicon (49 BC)
- Ides of March (March 15, 44 BC)
- Second Triumvirate (43 BC)
- Battle of Actium (31 BC)
Therefore, the correct response is:
Gracchi brothers’ assassinations, Sulla’s march on Rome, First Triumvirate, march across the Rubicon, Ides of March, Second Triumvirate, Battle of Actium.