What river sepurate Guyana form each of her immediate countinent neighbours?

Guyana is bordered by three countries: Venezuela to the west and north, Suriname to the east, and Brazil to the south. The rivers that separate Guyana from these countries are as follows:

- Venezuela: The Cuyuni River forms a natural border between Guyana and Venezuela. It rises in the highlands of Venezuela and flows northwards, eventually joining the Essequibo River in Guyana.

- Suriname: The Courantyne River forms the border between Guyana and Suriname. It originates in the Acarai Mountains in Brazil and flows northwards, eventually entering the Atlantic Ocean.

- Brazil: The Takutu River forms the border between Guyana and Brazil. It originates in the Serra da Pacaraima mountains in Brazil and flows northwards, joining the Rio Branco River in Brazil.