A relationship in which two different organisms live in close association with each other is called symbiosis.

Symbiosis can be further categorized into three main types:

* Mutualism: Both organisms benefit from the relationship.

* Commensalism: One organism benefits, while the other is neither harmed nor helped.

* Parasitism: One organism (the parasite) benefits at the expense of the other (the host).

Let me know if you'd like to know more about any of these types of symbiotic relationships!