Certain species of acacia trees in central and south america have hollow thorns that house stinging ants, which attack anything that touches the tree. the ants feed on nutrients produced by the acacias. this is an example of

It is an example of a mutualistic association

Explanation:

Mutualism is a form of ecological interaction that involves two species of organism in which the two organisms benefits from the association by working together. The Acacia species with hollow thorns house the stinging ants which protects the Acacia tree from external enemies and the stinging ants benefit by feeding on the plants nutrient and also receive accommodation from the acacia tree. The two species benefit by working together, Acacia tree benefit by receiving protection from external dangers and the ants benefit by receiving accommodation and food.