1) The concept of proportional representation, used in some electoral systems, aims to ensure that political parties' representation in government aligns more closely with the proportion of votes they receive from the electorate.

2) The President of the United States serves as the head of state and the head of government, responsible for leading the executive branch and representing the nation domestically and internationally.

3) The political system of the People's Republic of China is based on the Communist Party's leadership, with the General Secretary holding significant authority and influence over the country's policies and governance.

4) The smallest unit of time is known as a zeptosecond, which is equal to one trillionth of one billionth of a second.