What are the two broad categories into which coevolutionary interactions generally fall?

Answer

Antagonism and mutualism

Coevolutionary interactions are broadly categorized based on the fitness outcome for the participants: antagonism, where one benefits at the other's expense, or mutualism, where both parties benefit overall.

What are the two broad categories into which coevolutionary interactions generally fall?
speciesEcologyEcosysteminteractioncoevolution