| Answer | % Correct |
|---|---|
| Ohio | 72%
|
| Arkansas | 69%
|
| Red | 45%
|
| Brahmaputra | 41%
|
| Negro | 28%
|
| Tocantins | 28%
|
| Paraguay | 21%
|
| Madeira | 17%
|
| Kasai | 14%
|
| Pilcomayo | 14%
|
| Ubangi | 10%
|
| Japurá | 7%
|
| Juruá | 7%
|
| Katun | 7%
|
| Lower Tunguska | 7%
|
| Tarim | 7%
|
| Aldan | 3%
|
| Ishim | 3%
|
| Purús | 3%
|
| Vilyuy | 3%
|