Which of the following plants has become a water weed in this country?

Since the origin and diversification of life on Earth, there have been five episodes of mass extinction of species. How is the sixth extinction, which is in progress, different from the previous episodes?

In Lake Victoria of East Africa, more than $Y$ species of $X$ fish became extinct together. Identify $X$ and $Y$.

In the modern era,who is the greatest predator of humans in the world?

Discuss one example,based on your day-to-day observations,showing how the loss of one species may lead to the extinction of another.

Extinction of more than $200$ species of cichlid fish in Lake Victoria was due to the introduction of: