1. which problem contributed to rome's transition from a republic to an empire?

consuls staying in power too long

slave revolts

epidemics

natural disasters

2. what did julius caesar do that hastened rome's transition from a republic to an empire?

he appointed allies and friends as provincial governors.

he crossed the rubicon and defeated his enemies.

he declared himself dictator for life and first citizen.

he did away with rome's written laws.

1)  I am pretty sure that the problem which  contributed to Rome's transition from a republic to an empire is being revealed by the option one : consuls staying in power too long. I choose this option because only this option is closely connected with main characters from this event :  Marius, Sulla, and the Triumvirs. 

2) The thing which Julius Caesar did that hastened Rome's transition from a republic to an empire is being shown in the option : He crossed the Rubicon and defeated his enemies. I think this is correct because he let  a civil war out towards republic. 
Do hope you sill need the answer because this one will definitely help you!