1) The concept of gravity was famously described by Sir Isaac Newton after an apple fell on his head.

2) The word "mountain" contains three vowels: O, U, and A.

3) The English alphabet has five vowels: A, E, I, O, and U.

4) The ongoing conflict in Syria, which began in 2011, has resulted in a humanitarian crisis, displacement of millions of people, and international efforts to bring about a resolution and provide aid to those affected.