The Relationship: Squirrels and Pine Trees

* Commensal: The squirrel.

* Host: The pine tree.

How it Works:

* Squirrels often build nests in the branches of pine trees. This provides the squirrel with a safe and sheltered place to live, raise young, and store food.

* The pine tree is neither harmed nor benefited by the squirrel's presence. The squirrel's nest does not significantly impact the tree's growth or health.

Therefore, this relationship exemplifies commensalism because one organism (squirrel) benefits from the relationship, while the other (pine tree) is neither harmed nor benefited.