Answer: A species which other species in an ecosystem depend on.
Explanation:
A keystone species is a species that other species in the ecosystem depend on. Without these keystone species, the ecosystem may fall apart. Examples of keystone species include wolves, bees, sea otters, starfish, and so many more.
A species that is not indigenous to a particular area is a non-native species, and if this species is causing harm it is an invasive species. The maximum size of a population that an environment can support is the carrying capacity (K) of the environment. Lastly, a group of individuals of the same species existing together in the same place at the same time is a population.