1) International relations encompass the study of relationships between nations, including diplomacy, treaties, and foreign policy. It examines the interactions and dynamics among different countries in the global arena.

2) Tom Hanks is an American actor and filmmaker known for his versatile performances in films such as "Forrest Gump," "Saving Private Ryan," and "Cast Away." He has received numerous awards, including Academy Awards, Golden Globes, and BAFTAs.

3) The COVID-19 pandemic has highlighted the importance of global collaboration and solidarity in addressing public health emergencies, with efforts focused on vaccine sharing, equitable distribution, and support for developing countries.

4) 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.