Question

the one particular species that maintains the stability in the ecosystem

keystone species

tertiary consumer

apex predator

Explanation:

A keystone species is one that has a disproportionately large effect on its environment relative to its abundance. It plays a crucial role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and numbers of various other species in the community. A tertiary consumer is an organism that is at the top of the food chain and mainly eats secondary consumers. An apex predator is a predator at the top of a food chain, with no natural predators of its own. But the key here is the role of maintaining ecosystem stability which is specifically the definition of a keystone species.

Answer:

Keystone Species