Answer:
PARASITISM
Explanation:
Interactions between organisms of same and different species occurs in an ECOSYSTEM. However, this relationship can either be of benefit or loss to the organisms involved. A kind of relationship in which one of the organisms benefits at the detriment of another is called PARASITISM. In a parasitic relationship, the organism that benefits is termed the PARASITE while the deprived organism is termed the HOST.
In this question, the fleas and dog are the involved organisms. The flea attaches to the body of the dog for shelter and sucks its blood for nourishment. The flea benefits from the dog while the dog is deprived of its nutrient. Hence, this kind of relationship can be referred to as PARASITIC RELATIONSHIP where the flea is the parasite and the dog, the host.
