1) The first successful mass-produced personal computer, the IBM PC, was introduced in 1981 and played a significant role in popularizing the use of computers in homes and offices.

2) Mountains are formed through various geological processes, including tectonic plate movements, volcanic activity, and erosion.

3) The destructive power of cyclones is often attributed to their storm surge, which is a rise in sea level caused by the strong winds and low atmospheric pressure.

4) The word "orange" contains three vowels: O, A, and E.