Valency markers are affixed to the verb root either to increase or decrease valency. Finals are suffixes which encode transitivity, animacy, and valency. The valency of a verb is related to transitivity. The final includes transitivity and animacy markers, and valency markers. The concept of valency is related to transitivity. In contrast to valency, the transitivity of a verb only considers the objects. The number of arguments that a verb takes is called its "valency" or "valence". The valency of predicates is also investigated in terms of subcategorization. The causative morpheme allows an increase of valency of this predicate. In non-ionic crystals it refers to lattice valency defects. Lennard-Jones is well-known among scientists for his work on molecular structure, valency and intermolecular forces. Totonacan languages have a wide assortment of morphemes for increasing the valency of a verb. I Valency may be passive or causative. Most Nahuatl varieties have a number of ways to alter the valency of a verb. Most languages provide a means to change the valency of verbs.