An orchid plant is growing on the branch of a mango tree. How do you describe this interaction between the orchid and the mango tree?

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

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

Who proposed the Competitive Exclusion Principle?

Describe competition.

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$:
Assertion $(A)$: Recent studies do not entirely support the Gause's 'Competitive Exclusion Principle' in nature.
Reason $(R)$: Recent studies of competition rule out the occurrence of interspecific competition in nature.
In the light of the above statements,choose the most appropriate answer from the options given below:

The presence of flagellated protozoans in the gut of termites is an example of: