1) In Norse mythology, Ragnarok is a cataclysmic event that signifies the end of the world. It involves a series of apocalyptic battles and natural disasters, leading to the destruction of the gods and the world as it is known. From the ashes, a new world and a new generation of gods emerge.

2) The ozone layer, located in the Earth's stratosphere, protects us from harmful ultraviolet (UV) radiation.

3) Banks play a vital role in the economy by facilitating the flow of funds between savers and borrowers, providing loans, and offering various financial services.

4) The role of the judiciary is to interpret laws, resolve disputes, and ensure justice in accordance with legal principles and the constitution. It serves as a check on the executive and legislative branches of government.