Question

The exotic species, which when introduced in India became notorious weed, is
A. Lantana camara
B. Eichhornia crassipes
C. Parthenium hysterophorus
D. All of these

Answer 1

Hint:An exotic species is the one that usually is not native and is introduced from its native land to a new land. These species cause negative effects on the environment of their new habitat and hence are called invasive. These are referred to as weeds which means undesirable. Many of the species have been introduced in Indian habitats in previous decades that turned out to be invasive. These species include Verbenaceae sp., water hyacinth, Asteraceae sp.

Complete answer:An invasive species is referred to as a non-native species that spreads from a point of introduction to invade the new habitat and alter it negatively. They are usually introduced for beneficial purposes but can lead to environmental, ecological, and economic damage. They pose a serious economic, social, and environmental threat. Thus, they need to be studied properly and managed sustainably.
Lantana camara belonging to Verbenaceae sp. a native species in South America was introduced to Indian habitats by the British as an ornamental plant. It was around 200 years ago when the Forest officials in different parts of the country watched helplessly the uncontrollable spread of this species. This invasive plant spread endlessly with all efforts for its control going in vain.
Eichhornia crassipes also known as water hyacinth native to the Amazon basin is an aquatic plant. It grows invasively throughout the water bodies covering all of the top surfaces. This devoids the aquatic life of oxygen resulting in a decline in the number of fish. It was introduced in Bengal for its beautiful flowers and leaves. Later it turned out to be an invasive weed that drains all of the oxygen from the water bodies resulting in the death of fish. In Bengal, fish makes a major supplement of food. Thus, this invasive weed is termed out to be highly problematic. It is also called “Terror of Bengal”.
Parthenium hysterophorus which is a member of the aster family or Asteraceae sp. is a flowering plant that is native to the American tropics. It first appeared as an invader as a contaminant in wheat imported from America. The weed later turned out to be an invasive species that can grow on disturbed land, including roadsides. It can infect pastures and farmland becoming equally dangerous for all flora and fauna. It is also dangerous for humans. It leaves the soil where it grows infertile.

Therefore, from the above discussion, we can conclude that the right answer is option D.

Note: Invasivorism is a movement that uses the idea of eating invasive species to control and reduce their growth. The invasive species have also been used by chefs as alternative ingredients. An organization like Reef Environmental Educational Foundation has published cookbooks that include invasive species as an ingredient in recipes.