1) The concept of political stability refers to the ability of a government or political system to maintain continuity, order, and effective governance over a prolonged period, promoting social cohesion and economic development.

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

3) The Cricket World Cup is held every four years and features teams from around the world competing for the prestigious title.

4) The first commercially available digital camera, the Dycam Model 1, was introduced in 1990 and had a resolution of 376 x 240 pixels.