$A$ : Cattle or goat never graze on Calotropis.
$R$ : Thorns are present as a morphological means of defence

$A$ : Fig species and wasp have tight one to one relatioinship.
$R$ : Angiosperms and insects are coevolved to perform a plant-pollinator interaction.

Which of the following is an example of a defence used by plants against herbivores?

$I.$ Production of caffeine, tannin quinine

$II.$ More production of non-woody tissues

$III.$ Productions of hairs, thorns, spines

$IV.$ Production of hormone-like chemicals that interfere with insect metamorphosis

Select the correct pair

Given below are two statements:

Statement $I$: Gause's competitive exclusion principle states that two closely related species competing for different resources cannot exist indefinitely.

Statement $II$: According to Gause's principle, during competition, the inferior will be eliminated. This may be true if resources are limiting.

In the light of the above statements, choose the correct answer from the options given below :

Within biological communities, some species are important in determining the ability of a large number of other species to persist in the community. Such species are called