Nitric oxide (NO) Nitric oxide (NO), colourless, toxic gas that is formed by the oxidation of nitrogen. Though it has few industrial applications, nitric oxide performs important chemical signaling functions in humans and other animals and has various applications in medicine.
or British mollusc /ËmÉËlÉsk/. plural mollusks. Learner's definition of MOLLUSK. [count] biology. : any one of a large group of animals (such as snails and clams) that have a soft body without a backbone and that usually live in a shell.
Slug is a common name that is normally applied to any gastropod mollusk that lacks a shell, has a very reduced shell, or has a small internal shell. Snail is a common name for almost all gastropod mollusks that have coiled shells in the adult stage.When the word is used in a general sense, it includes sea snails, land snails and freshwater snails.dit Anatomy. The only significant morphological difference between the slug and the snail is the snailâs conspicuous shell. This shell is large enough for the snail to completely retract into for defense.