The main components of a parliamentary system of government include an elected parliament, an executive derived from the legislature, and a head of state who is separate from the head of government. The parliament is responsible for making laws, while the executive, often led by a prime minister, implements these laws and manages the government. This system emphasizes accountability, as the executive is directly answerable to the legislature and can be removed by a vote of no confidence. This interconnectedness promotes cooperation between branches and enables a swift response to changing political situations, enhancing governance.