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

Symbiosis can be further categorized into different types, depending on how the organisms benefit or are affected by the relationship:

* Mutualism: Both organisms benefit from the relationship. (Example: Bees pollinating flowers)

* Commensalism: One organism benefits, while the other is neither harmed nor helped. (Example: Barnacles attached to whales)

* Parasitism: One organism benefits at the expense of the other. (Example: Tapeworm living in a human's intestines)

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