What term describes the relationship where two species live in close association and may coevolve?

The term that describes the relationship where two species live in close association and may coevolve is symbiosis. Symbiosis encompasses various types of interactions between organisms, which can be beneficial, neutral, or harmful to one or both parties involved. This relationship can lead to coevolution, where the evolution of one species directly influences the evolution of another, resulting in adaptations that enhance their interdependent relationship.

In the context of symbiosis, mutualism is a subtype where both species benefit, while commensalism is another subtype where one species benefits and the other is neither helped nor harmed. However, the broader concept of symbiosis includes all possible types of close biological interactions between species, making it the most appropriate term to describe the relationship involving coevolution. Thus, symbiosis captures the essence of these close associations and the potential for evolving together over time.