Its started after World War 2 because after a lot of issues arose between the US and USSR. They had a mutual distrust with each other stemming from the way the US had perceived the USSR as an illegitimate part of the international community. The way the USSR perceived the US as people who intervened in everyone's business and had amounted weapons.
Answer:
Global life expectancy is the average age that people live to be. This is not a national life expectancy where we look only at one country and is on a global level. The industrial revolution impacted life expectancy by raising wages, living conditions. New technology was invented and many breakthroughs in sanitation were made.
