Answer:
PARASITISM
Explanation:
In an ecosystem, organisms of same or different species tend to interact with one another. The interaction between two organisms is termed SYMBIOSIS. A symbiotic relationship can further be divided into types depending on the effect on the interacting organisms. The symbiotic relationship that depicts the explanation in this question is PARASITISM.
PARASITISM is a kind of symbiotic relationship in which one of the organisms benefits in expense of the other i.e. the other organism loses due to the action of the benefitting organism. The organisms that benefits from this type of relationship is called the PARASITE while the organism that loses is called the HOST.
This is the case in this question involving a dog and tapeworm. The tapeworm lives in the intestine of the dog and absorbs the digested nutrients of the dog. The tapeworm gains by getting nutrients at the expense of the dog's health. The dog is deprived of its nutrients and starts getting lean. In addition, the tapeworm causes several illnesses to the dog. In this relationship, the tapeworm referred to as the PARASITE gains while the dog referred to as the HOST loses. Hence, it is a PARASITIC relationship.
