Relative movement of the in the semicircular ducts signals rotation of the head.

Relative movement of the endolymph in the semicircular canals signals rotation of the head. However disruption of the endolymph due to irregular activities (like spinning around or driving over bumps while riding in a car) can cause illness. An disease where the capacity of the endolymph is critically inflated is called endolymphatic hydrops and has been linked to Ménière's disease.

D.) domain, kingdom, phylum, class, order, family, genus, species