Where is most of the population clustered in East Asia?
along the rivers and coast
Arabia, or the Arabic world, are the countries in the world that are inhebited by Arabic speaking population. It includes parts of Asia and Africa. Most of the middle east is a part of the Arabic world (The eastern part). However, there are a couple of countries in the Middle East that are NOT a part of the Arabic world, such as Afghanistan and Pakistan...
Roughly speaking, north Africa and southwest Asia. Please see the link. It depends what the person means by "most". If they are referring to the largest populations of Muslims, the best places to look would be South Asia and Indonesia. If you are looking for places where the largest percentage of the overall population is Muslim, then the Middle East and North Africa is correct.
Asia is one of the biggest continents and its conformed by 47 countries. Of them all, the most populated one is China, with a population of 1,357,379,000 as projected by July of 2013. Following China, there are India, with a population of 1,257,476,000, Indonesia, with 248,731,000, Pakistan, with 183,936,000, Bangladesh, with 154,514,000, Japan, with 127,350,000, and The Philippines, with a estimated population of 98,000,005.