What makes bones so strong?

Correct Answer: D

Rationale: Bones’ strength comes from calcium and phosphorus in hydroxyapatite, forming a hard matrix. Silica is minimal, cartilage is flexible, blood/marrow fill spaces—not strength sources. 'Calcium and phosphorous' is correct.

Correct Answer: A

Rationale: The coronal suture runs transversely, separating the frontal bone from the parietal bones, and extends from the anterior fontanel (top center) toward the anterolateral fontanels (sides). The lambdoidal suture is posterior, squamosal is lateral, and longitudinal isn’t a standard cranial suture term (likely meant sagittal).

Correct Answer: C

Rationale: The superior and middle conchae (turbinates) are projections of the ethmoid bone in the nasal cavity, aiding air filtration. The inferior concha is separate, while palatine, nasal, and maxilla bones don’t form these structures.

Correct Answer: D

Rationale: The cribriform plate, perforated for olfactory nerves, is part of the ethmoid bone. Sphenoid, maxilla, temporal, and vomer lack this structure.

Correct Answer: A

Rationale: Lordosis is an exaggerated inward curvature of the lower spine (lumbar region). Scoliosis is lateral deviation, kyphosis is outward curvature (hunchback), and spina bifida is a congenital defect, not a curvature.