Answer:
coevolution
Step-by-step explanation:
The answer is "coevolution".
When two or more organisms or species affects their evolution collectively as a result of interaction between them. The term "coevolution" is first given by Peter H. Raven and Paul R. Ehrlich.
Charles Darwin stated the interconnection between the insects and the flowering plant as a similar scenario of coevolution.
Thus the ants who lives on the acacia trees and feeds on its leaf structures rich in lipids and protects the trees from other predators. They shows coevolution relationship.
Thus the answer is "coevolution".