Question

What is meant by "alien species" invasion? Name one plant and one animal alien species that are a threat to our Indian species.

Answer 1

Intentional or chance introduction of exotic species into new islands or countries by man is alien species invasion.
For example, Nile perch introduced into Lake Victoria in East Africa which caused loss of more than 200 species of cichlid fish.

Plant alien species - Lantana camara
Animal alien species: Clarias gariepinus