Which of the following communities is more vulnerable to invasion by outside animals and plants?

Select the incorrect option for water hyacinth (Eichhornia crassipes).

Which phenomenon was observed in Lake Victoria of East Africa?

The most dramatic example of biodiversity loss from tropical rain forests is because of:

Match the column $I$ with column $II$:

Column $I$	Column $II$
$(a)$. Thylacine	$(i)$. Russia
$(b)$. Dodo	$(ii)$. Mauritius
$(c)$. Quagga	$(iii)$. Australia
$(d)$. Steller's sea cow	$(iv)$. Africa

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.