$A$ scorpion stalks,kills,and then eats a spider. Based on its behavior,which ecological terms describe the scorpion?

When pheromones are secreted onto the skin surface,their scent affects . . . . . . .

Predators also help in $A$ species diversity in a community,by $B$ the intensity of competition among competing prey species. Here $A$ and $B$ can be

$A$ high density of elephant population in an area can result in

Statements
$I.$ Recent studies support competition as suggested in 'Gause's Competitive Exclusion Principle'.
$II.$ Gause's hypothesis states that if two species compete for the same resources,then one will be eliminated by the other species.
$III.$ More recent studies point out that species facing competition might evolve mechanisms that promote co-existence rather than exclusion.
$IV.$ Gause's competitive exclusion principle is effective when resources are in excess.
$V.$ Unlimited resources give better opportunity for adaptation.
Choose the correct combination of statements.

In an intertidal area, when all starfish were removed, more than $Q$ species of invertebrates became extinct within a year due to $P$.