If the high-altitude birds become rare or extinct,the plants which may disappear along with them are

The exotic species $Eichhornia \text{ } crassipes$:

Assertion: Tropical rain forests are disappearing fast from developing countries such as India.
Reason: No value is attached to these forests because these are poor in biodiversity.

Statement $(A)$: The Caspian tiger, a subspecies of tiger, is one of the recently extinct animals.
Reason $(R)$: The colonization of tropical Pacific islands by humans.

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

The colonisation of tropical........ by humans is said to have led to the extinction of more than $2000$ species of native birds.