Final answer:
Military service length varied across countries and time periods. In Russia, it could last several years, while in France it was usually three years. Other countries like Egypt, Switzerland, Turkey, and Singapore also had mandatory military training and service.
Step-by-step explanation:
In different countries and time periods, the length of military service has varied. For example, in Russia and France during certain periods, it was compulsory for men to serve in the military.
In Russia, military service could last up to several years. In France, at one point, it required three years of service from all men. After completing the compulsory service, individuals were classified as reservists and could be mobilized if necessary.
In other countries, such as Egypt, Switzerland, Turkey, and Singapore, youths, usually males, are expected to undergo several months or years of military training and service.