Symbiosis is a close and often long-term interaction between two different biological organisms. It can be categorized into three main types:

* Mutualism: Both organisms benefit from the relationship. For example, bees pollinate flowers, getting nectar in return.

* Commensalism: One organism benefits, while the other is neither harmed nor helped. For instance, barnacles living on the skin of whales.

* Parasitism: One organism (the parasite) benefits at the expense of the other (the host). For example, a tapeworm living in the intestines of a human.

Symbiosis is a complex and diverse phenomenon found throughout the natural world, playing a crucial role in shaping ecosystems and driving evolution.