Questions

There   are five known   states   of matter:    solids,    liquids,    gases, plasma and Bose-Einstein condensates.  The  main  difference in the structures of each state is in the densities of the particles.

Glaucoma is usually caused by high pressure on the optic nerve which leads the loss of eye sight.

An electric arc is a visible plasma discharge between two electrodes that is caused by electrical current ionizing gasses in the air. Electric arcs occur in nature in the form of lightning.

National security refers to security of a nation state, including its citizens, economy&institutions, is regarded as a duty of govt. It is celebrated every year on 4th March. The 1st National Security Day observed in the year 1972.

The Cold War started with building tensions between the US and the USSR during World War II. As Stalin began to annex more countries and spread communism throughout Eastern Europe, the US began to feel threatened and feared that they would start a war amongst the capitalist nations. The US started an attempt to limit the spread of communism and protect capitalism, which led to a series of passive aggressive and indirectly hostile exchanges between the two nations.

The beginning of the end of the cold war, the Berlin Wall came down. The USSR began to collapse the following year, in 1990.