Why is water hyacinth called the 'Terror of Bengal'?

Identify the correct types of ecological interactions represented by $P$,$Q$,$R$ and $S$.

Interaction between Species $A$ and Species $B$	Type of interaction
$+$,$-$	$P$
$-$,$-$	$Q$
$+$,$0$	$R$
$-$,$0$	$S$

What is the significance of mimicry?

Which one of the following is most appropriately defined?

Given below are two statements:
Statement $I:$ Gause's 'Competitive Exclusion Principle' states that two closely related species competing for the same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually.
Statement $II:$ In general,carnivores are more adversely affected by competition than herbivores.
In the light of the above statements,choose the correct answer from the options given below:

What are the organisms that feed on plant sap and other plant parts called?