Meaning of 先進国 in Japanese

Cavities have become rarer in the developed countries and more people will be able to eat with their own teeth throughout their life.

Japanese cameras, cars, and hi-fi equipment are used widely abroad, and few modern industries can manage without advanced electronic equipment developed in Japan.

Many developed countries are faced with financial crises.

While the birth rate is intended to be decreased in developing countries, that of developed nations is selfishly planned to be increased, resulting in the difficulty of getting mutual consent.

Advanced countries must give aid to developing countries.

The countries should aid the countries much more.

Until quite recently, people in developed countries didn't care much about the environment.