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

$Parthenium$ (carrot grass) that came into India has become ubiquitous in occurrence and causes pollen allergy.

When a host fish species becomes extinct,its unique assemblage of parasites also meets the same fate. This is an example of:

Which endangered animal is the source of the world's thinnest, lightest, warmest, and most expensive wool?

Many species like $Steller's$ sea cow and passenger pigeon have been driven to the brink of extinction. Which of the following describes this situation?

The recent illegal introduction of the African catfish $Clarias$ $gariepinus$ for aquaculture purposes is posing a threat to the indigenous catfishes in our rivers.