Answer:
1. rivers, coastlines and several archipelagos
3. Indonesia is an archipelago which is located in the Southeast Asia, next to Singapore, Malaysia, Brunei Darussalam , East Timor and Papua New Guinea .
12. The culture in Southeast Asia is very diverse: on mainland Southeast Asia, the culture is a mix of Burmese, Cambodian, Laotian and Thai and Vietnamese cultures. While in Indonesia, the Philippines, Singapore and Malaysia the culture is a mix of indigenous Austronesian, Indian, Islamic, Western, and Chinese cultures.
13. Southeast Asian art and architecture includes works from the geographical area including the modern countries of Thailand, Cambodia, Laos, Vietnam, Myanmar (formerly Burma), Malaysia, Singapore and Indonesia. The area is also known as Indochina. The art of this region draws from three major sources: indigenous traditions, China, and India.
2. Hwang He (Yellow River), Chang-Jiang (Long River/Yangtze), and Xi Jiang (West River)