Final answer:
Montesquieu's concept of separation of powers delineates distinct roles for the legislative, executive, and judicial branches of government, designed to maintain liberty and prevent tyranny.
Step-by-step explanation:
According to Montesquieu, the roles of the branches of government include the legislative function, which is tasked with creating and amending laws; the executive function, responsible for maintaining public security by enforcing the laws; and the judicial function, which has the duty to punish criminals and settle disputes. Montesquieu emphasized the concept of separation of powers, stating that these three branches should each hold distinct responsibilities and powers, operating as a system of checks and balances to maintain liberty and prevent the rise of despotic rule.