Which one is an example of alien species?

The correct option is D

All of the above

The correct option is D.

Explanation for the correct option:

1. Alien species are non-native species that have been introduced into a region, either purposefully or accidentally.
2. Invasive alien species can sometimes become invasive, resulting in the extinction or decline of native species.
3. The introduction of Nile perch into East Africa's Lake Victoria resulted in the loss of 200 cichlid fish species.
4. African catfish have been introduced into Indian rivers, posing a threat to native catfish species.
5. An invasive floating plant known as a water hyacinth can be found in water bodies all over the world.
6. These invasive species seriously damage a variety of ecosystem lifeforms by preventing sunlight from entering and oxygen levels from rising in water systems.

Final answer: Introduction of water hyacinth into India, the introduction of Nile perch into Lake Victoria in East Africa, and the introduction of African catfish into Indian Rivers are all examples of alien species.