Paranasal sinuses present at bih ?

Ans. is 'b' i.e., Ethmoid and maxillary Maxillary sinus - 4 Develop at bih; completely develop at 9 years Ethmoidal sinus - Develop at bih; completely develop at late pubey Frontal sinus - Develop at 2 year; completely develop at late adolescence Spenoid sinus - Develop at 3-5 years; completely develop at 12-15 years