When the Nile perch was introduced into Lake Victoria in East Africa,it led to the extinction of an ecologically unique assemblage of more than $.............$ species of cichlid fish in the lake.

Among the following plants,which one would you consider an endangered plant due to over-exploitation?

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

According to the $IUCN$ Red List,in which category is the Red Panda $(Ailurus fulgens)$ classified?

Which of the following statements is correct regarding Parthenium (Carrot grass)?
$(a)$ It was introduced into India as a contaminant with imported wheat.
$(b)$ It causes allergies.
$(c)$ Asexual reproduction occurs in its flower.

Why do exotic species sometimes become invasive and start spreading rapidly?