Question

most important organisms
an alligator is an example of a keystone species. what is the
definition of a keystone species?
a species that prefers to reside on top of or close to water
a species with no influence on the ecosystem and could be safely removed
a species with significant influence on the structure and functioning of the
ecosystem

Explanation:

A keystone species is defined by its significant influence on an ecosystem's structure and functioning. The first option about habitat preference is not the core definition. The second option is incorrect as keystone species have a major impact, not no influence. The third option aligns with the concept that a keystone species has a large - scale effect on maintaining the biodiversity and stability of its ecosystem.

Answer:

a species with significant influence on the structure and functioning of its ecosystem