What aspect of an organism makes it an invasive species?

it has no predators in the new ecosystem
it is from a different ecosystem
it does harm and is introduced to the ecosystem
it is harmfult to organisms in all ecosystems

All of the mentioned aspects can contribute to an organism being classified as an invasive species. An invasive species typically possesses characteristics such as having no natural predators in the new ecosystem, being introduced from a different ecosystem, causing harm to the native species or ecosystem, and being harmful to organisms in all ecosystems.