3. The species that has the biggest population is Pongo pygmaeus wurmbii

4. Each of the species live in:

- Pongo abelii lives in Sumatra island

- Pongo pygmaeus, Pongo pygmaeus morio, and Pongo pygmaeus wurmbii live in Kalimantan island 

5. The threats of Orangutan population include:

- Habitat conversion into plantation and infrastructure

- Habitat conversion into farming

- Forest fire 

6. The strategies to prevent the threats:

• Forest management
• Law enforcement
• Better landscape planning
• Law enforcement for farming
• Forest management

(TribunnewsBogor.com/Tia)