The species compete with each other. One species preys on the other. The species ignore each other. One species benefits from the other.
I gave my students this multiple choice question: Two populations of reef fish live in biological coexistence with each other. Which sentence best describes their relationship?

Only one answer is correct among these 4 choices:
- The species compete with each other.
- One species preys on the other.
- The species ignore each other.
- One species benefits from the other.

Could you tell me which one is correct?

The species ignore each other.