What is the type of interaction between a sucker fish (Remora) and a shark?

Which type of interrelation is observed in species $A$ $(+)$ and species $B$ $(-)$?

Which characteristic is observed in the $Gause's$ Competitive Exclusion Principle?

What does Gause's Competitive Exclusion Principle state?

Which of the following is an example of a defense used by plants against herbivores?
$I.$ Production of caffeine,tannin,quinine
$II.$ More production of non-woody tissues
$III.$ Production of hairs,thorns,spines
$IV.$ Production of hormone-like chemicals that interfere with insect metamorphosis
Select the correct pair.

Competition occurs when