Discuss each of the following interspecific relationships, including reference to the species involved, their role in the interaction, and the specific characteristics of the relationship:

(a) Mutualism between ruminant herbivores and their gut microflora

(b) Commensalism between a shark and a remora

(c) Parasitism between a tapeworm and its human host

(d) Parasitism between a cat flea and its host.