The fish migrated from the ocean The fish was unable to reproduce A mountain used to be in this area A river used to run through this area
What is the best conclusion that can be made upon discovering a fossil of a freshwater fish in a desert area?

Options:
- The fish migrated from the ocean
- The fish was unable to reproduce
- A mountain used to be in this area
- A river used to run through this area

A river used to run through this area