Answer: Parasitism
Step-by-step explanation:
Parasitism is a symbiotic relationship in which the two organisms belonging to different species lives in close association. In this association, one organism receives the benefit and the other is harmed. The organism which receives the benefit is the parasite and the organism which is harmed is the host.
Mistletoe is a parasite for the host plants. This causes the infection to the branches of the swollen plant species and makes the trees more susceptible to other insects infestation. This is an example of parasitism.