1) The Mongol Empire, under the leadership of Genghis Khan, became the largest contiguous empire in history, spanning from Asia to Europe.

2) Mountains are important water sources, as they capture and store precipitation, feeding rivers and supporting ecosystems downstream.

3) The corpse flower, or titan arum, is known for its unpleasant smell, often compared to that of rotting flesh.

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.