Parliamentary systems often work where the head of government is the leader of the political party with the most members in the parliament.
This support is usually shown by a vote of confidence. A balanced relationship between the executive and the legislature in a parliamentary system is called responsible government.
The separation of powers between the executive and law making branches is not as obvious as it is in a presidential system. There are different ways of balancing power between the three branches which govern the country (the executive (or ministers), the law makers and the judges).
Examples of a few countries which practice parliamentary systems are India, Italy, Japan, Germany, and Latvia. Parliament is different in every country.