Which threats of the biodiversity is a result of plants and animals introduced to an ecosystem where they are not normally found?

The answer is invasive species. Invasive species is when plants, fungus or animals that are not familiar or native to specific location and has a tendency to spread damage to environment, human health  and human economy. eg: Cane toads are originally from Australia and was moved to grasslands. These toads  are invasive species in Grasslands because they are destroying the environment and destroying the balance of wildlife (in Grasslands).

Invasive species are one of the threats to biodiversity and some ecosystems.

hope this helps
 

Idon't know it i just need my points lol

Iwould have to say sorry i can't elaborate more. hope this though!