Ques-1: A keystone species is defined as a species, which has an excessively large impact on its individual environment relative to its “own species abundance”. This has mutualistic relationship & enabling an important function in maintaining balance of their species in ecological community. The gardens of “fungus-growing leaf-cutter ants” form a complex community of coevolved species engaged in a variety of interspecific interactions for example, actinobacteria (bottom level of organization), the prokaryotic keystone species has mutualistic relationship to increase nitrogen supply that can control fungus by secreting “antibiotics”. Escovopsis fungi are going to consume cultivated fungus. Lepiotaceae family members, yeast are going to supply nutrients to growing ants and this fungus benefits fungus growing leaf cutter ants by destroying “actinobacteria” therefore, and top-down trophic levels of organization i.e. plants are going to get benefit from these keystone species A few predators have the ability to control other high population distribution by predation in the habitat and acts as “keystone species” in the ecosystem balance. Therefore, it has clearly observed from the above hypothesis, all the three species in the above are inter-related, mostly; a keystone species is useful to keep the ecosystem in balance. These predators have specific impact in maintaining ecosystem balance with major impact on the environment by reducing sea urchin high distribution. Solution Ques-1: A keystone species is defined as a species, which has an excessively large impact on its individual environment relative to its “own species abundance”. This has mutualistic relationship & enabling an important function in maintaining balance of their species in ecological community. The gardens of “fungus-growing leaf-cutter ants” form a complex community of coevolved species engaged in a variety of interspecific interactions for example, actinobacteria (bottom level of organization), the prokaryotic keystone species has mutualistic relationship to increase nitrogen supply that can control fungus by secreting “antibiotics”. Escovopsis fungi are going to consume cultivated fungus. Lepiotaceae family members, yeast are going to supply nutrients to growing ants and this fungus benefits fungus growing leaf cutter ants by destroying “actinobacteria” therefore, and top-down trophic levels of organization i.e. plants are going to get benefit from these keystone species A few predators have the ability to control other high population distribution by predation in the habitat and acts as “keystone species” in the ecosystem balance. Therefore, it has clearly observed from the above hypothesis, all the three species in the above are inter-related, mostly; a keystone species is useful to keep the ecosystem in balance. These predators have specific impact in maintaining ecosystem balance with major impact on the environment by reducing sea urchin high distribution..