As the image shows, Asia has many meanings, and it is not different when it comes to American studies. In this sense, the numbers reference differe...

As the image shows, Asia has many meanings, and it is not different when it comes to American studies. In this sense, the numbers reference different understandings of Asia, respectively:

West Asia, Central Asia, East Asia, and Eastern Asia

West Asia, South Asia, East Asia and Southeast Asia

East Asia, South Asia, West Asia, and Southeast Asia

East Asia, Southeast Asia, West Asia and South Asia

East Asia, Central Asia, West Asia and Southeast Asia.