What is required at the foundation for symbiosis to develop beyond mere proximity?

Answer

Proximity and repeated interaction where one lives in or on the other.

For symbiosis to truly emerge and influence evolutionary paths, it requires proximity combined with repeated interaction, specifically where one organism lives in or on the other or depends heavily on the other for survival.

What is required at the foundation for symbiosis to develop beyond mere proximity?
biologyevolutioninteractioncoevolutionsymbiosis