Symbiosis can be stated as the interactions among the two or more different species. The interactions is completely different compared to the normal and regular interactions among the species. In the symbiotic species the species live a complete different relationship among themselves. The species live together. There are involvement of different organisms that provides different benefits to different species which are living together. There are different interactions where the species living together are not benefitted rather they are harmed by each other. The relationship which is symbiotic in nature can be facultative and obligate. The obligate symbiosis can be stated as the interaction between the two species where the two species cannot live without one another. In case of the facultative symbiosis the species live willingly with one another. There are different types of symbiotic relationship such as commensalism, competition, mutualism and parasitism. In the mutualism both the species interacts with each other and are benefitted from one another. There are variety of interactions and are common in the nature. The example of such symbiotic relationship is lichen. In the commensalism only one of the species is benefitted however, the other species has no benefits. Example of such type is the grazing of the cattle. Where the cattle is benefitted and on the other hand the grass is harmed. In the parasitism relationship one entity stays at the top of the other entity. Different types of parasites are the example of this type of symbiotic relationship. The competition relationship is the one in which both the entities are living in the same ecosystem depending upon the same resources. Example of such relationship is when different types of the same species is living in an ecosystem and fighting to survive.