"They are fantastically diverse. They speak hundreds of languages and dialects. They comprise scores of ethnic groups. They include highly industrialised economies and up-and coming economics. They span half of the surface of the earth and are home to two-fifth of the world's population". The group of countries referred to here belongs to:
APEC stands for Asia-Pacific Economic Cooperation. The description in the question accurately portrays the vast diversity and geographical spread of the Asia-Pacific region.