1) 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.

2) The fingerprints of koalas are so similar to humans that they have been mistaken at crime scenes.

3) The word "umbrella" contains three vowels: U, E, and A.

4) The French Revolution, which began in 1789, marked a major turning point in European history, leading to the overthrow of the monarchy and the rise of republicanism.