Answer:
altruism
Step-by-step explanation:
i was stuck between mutuaism and alturism, but just boiled it down to alturism.
mutualism is where two or more species benifits, so like flowers and bees. but seeing how is just dolphins, it dosent make sense
alturism is where "behavior of an animal that benefits another at its own expense."
the dolphin is helping the other dolphin just because they can