Among below choices, which is false about isthmus of fauces?
A、Hard palate participates in composition of isthmus of fauces.
B、Isthmus of fauces is the narrow part between oral cavity and pharynx.
C、Isthmus of fauces constitutes the boundary between oral cavity and pharynx.
D、Uvula participates in composition of isthmus of fauces.
E、Root of tongue participates in composition of isthmus of fauces.