The soviet union took advantage of the location of the baltic nations by

The answer is: establishing naval bases there.

The baltic nations refers to the nations in Northern Europe that bordered by the Baltic Sea (such as  Estonia, Latvia, and Lithuania.).

These regions is really close to the western Europe which notoriously formed an alliance with united states. By establishing naval bases on the baltic nations, soviet union hope to be able to stop the upcoming attacks to their territories because all attacks from western Europe will had to pass through these Baltic regions.

d. stage 4

explanation:

the existence of some kind of demographic transition is widely accepted in the social sciences because of the well-established historical correlation linking dropping fertility to social and economic development.[1] scholars debate whether industrialization and higher incomes lead to lower population, or whether lower populations lead to industrialization and higher incomes. scholars also debate to what extent various proposed and sometimes inter-related factors such as higher per capita income,lower mortality, old-age security, and rise of demand for human capital are involved.[2]