Concept:Epiphytism is a relationship where one plant grows on another plant only for support and does not take nutrients from the host.
Explanation:A fern growing on a palm tree uses the palm purely as a physical anchor.
It obtains water and minerals from rain, air, and decaying matter around it, without harming the palm.
Therefore, fern on palm tree correctly represents epiphytism.
Lice on human hair show parasitism, as they feed on the host.
Mistletoe on citrus fruit is a parasitic plant relationship.
Egret on cow is commensalism, where the egret benefits while the cow is unaffected.
These are not examples of epiphytism.
Answer:D. Fern on palm tree