Consider the following statements regarding plant secondary metabolites and identify which are correct.

I. Cyanogenic glycosides deter predators or herbivores primarily through the emission of hydrogen cyanide (HCN) when the plant is damaged.

II. Glucosinolates, upon hydrolysis by a specific enzyme called myrosinase, release volatile substances responsible for the pungent smell and taste of vegetables like cabbage and broccoli.

III. The first step in enzymatic breakdown of cyanogenic glycosides involves cleavage by hydroxynitrile lyase, directly releasing cyanide.

IV. Nonprotein amino acids, such as canavanine, exert their toxicity by being mistakenly incorporated into proteins in place of their natural counterparts, disrupting the proteins' structure and function.