Answer:
To maintain a national majority is not a reason for policies to decrease or limit population growth.
Explanation:
The demographic trends in each country are unique, though the differences can be very small or pretty large between them. Some countries have had problems or are now facing a problem with exponentially growing populations, so the governments simply had to enact policies to stop that trend and try to decrease or limit the population growth.
There are multiple reasons that would lead a government to enact such a policy, but all of them can simply be put as existential reasons. Every country has limited resources and territory suitable for living, thus there is a limit as to how much the population can grow and to not come in a situation where there will be a lack of natural resources, food, water, or place to live. Also, if a country is doing well economically, if the population doesn't grow exponentially, the chances are much higher that the standard of living will increase. The best example of a country that has enacted such a policy is China.
