1) The national animal of Australia is the kangaroo.

2) 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.

3) The novel "To Kill a Mockingbird" by Harper Lee has been translated into more than 40 languages and has sold over 40 million copies worldwide.

4) The Arctic Ocean is the smallest and shallowest ocean, located at the North Pole. It is covered by sea ice for much of the year.