What aspect of an organism makes it an invasive species?

Responses

It does harm and is introduced to the ecosystem.
It does harm and is introduced to the ecosystem. - no response given

It is harmful to organisms in all ecosystems.
It is harmful to organisms in all ecosystems. - no response given

It is from a different ecosystem.
It is from a different ecosystem. - no response given

It has no predators in the new ecosystem.

It has no predators in the new ecosystem. - no response given