The major religion in mainland Southeast Asia is Buddhism.
The major religion in mainland Southeast Asia is Buddhism. To find this answer, you can start by conducting a search on the internet using keywords such as "major religion in mainland Southeast Asia." This will give you a list of search results that you can click on to gather more information. Additionally, you can consult reliable reference books, encyclopedias, or academic articles on the topic. These resources will provide you with detailed explanations and data about the major religion in mainland Southeast Asia.
