Which of the following is an example of predation?

Examples of chemicals produced by plants as a defense against grazers and browsers:
$I.$ Nicotine
$II.$ Caffeine
$III.$ Quinine
$IV.$ Strychnine
$V.$ Opium
Choose the correct combination.

In an aquarium,two herbivorous species of fish are living together and feeding on phytoplanktons. As per the Gause's Principle,one of the species is to be eliminated in due course of time,but both are surviving well in the aquarium. Give possible reasons.

In an association of two animal species,one is a termite which feeds on wood and the other is a protozoan $Trichonympha$ present in the gut of the termite. What type of association do they establish?

Given below are two statements:
Statement $I$: Competition can be defined as a process in which the fitness of one species is significantly lower in the presence of another species.
Statement $II$: According to Darwin,interspecific competition is a potent force in organic evolution.

The interaction between "Cuckoo and Crow" is an example of: