What is the difference between an introduced and an invasive species?

Question

A. An introduced species is not necessarily harmful to the environment; an invasive species has a negative effect.
B. An introduced species is brought in on purpose; an invasive species has been there a long time
C. An introduced species is added in by humans; an invasive species enters new ecosystems on its own
D. An introduced species is added in by humans; an invasive species enters new ecosystems on its own

Answer 1

C. An introduced species is added in by humans; an invasive species enters new ecosystems on its own

This is the main difference between the two terms. Introduced species are deliberately or accidentally brought into a new environment by humans, while invasive species spread on their own and often have negative impacts on the local ecosystem.