Commensalism is a type of symbiotic relationship between two organisms where one organism benefits and the other is neither harmed nor benefits. In this relationship, one organism is referred to as the commensal, which benefits by obtaining resources, shelter, or transportation from the other organism called the host. The host is unaffected by the presence of the commensal. An example of commensalism is when a bird builds a nest in a tree. The bird benefits by having a safe place to lay eggs and raise young, while the tree is unaffected by the bird's presence.
