Question

what are the structures that are air - filled spaces of the skull bones?
a sutures
b fontanels
c sinuses
d lacrimal ducts

Explanation:

Sutures are fibrous joints between skull - bones. Fontanels are soft spots in an infant's skull. Lacrimal ducts are related to tear - production. Sinuses are air - filled cavities in the skull bones.

Answer:

C. Sinuses