Question

1. what is the longest and only river in the world that flows north?

Explanation:

The question is about a geographical fact related to a river. The Nile River is the longest river in the world and it flows northward. It's a key geographical feature, so the subfield of Geography (under Natural Science) applies here. The Nile is known to flow from south to north, and it's the longest river, matching the description in the question.

Answer:

The Nile River