Answer:
Mutualism
Step-by-step explanation:
Organisms of same or different species tend to interact in their natural environment. They form relationships that benefits or harms them. The relationship between two organisms is referred to as SYMBIOSIS. A type of symbiotic relationship is one in which both organisms involved benefits from the relationship. This kind of symbiotic relationship is called MUTUALISM.
This mutualistic relationship is the case here, where both the bullhorn acacia tree and acacia ants provide services that benefits both organisms. The acacia tree houses the acacia ants, providing them with shelter and food in form of highly nutritious nectar and in return the acacia ants protect the tree by helping drive away predators or herbivores.