Which type of junction prevents substances from passing between cells?

Correct Answer: C

Rationale: Tight junctions form impermeable seals between adjacent cells, preventing substances from leaking between them, as in the gut lining to block bacteria. Gap junctions allow communication via channels for ions/small molecules, not sealing. Desmosomes anchor cells mechanically, resisting stress, not blocking passage. Hemidesmosomes tether cells to the basement membrane, not each other. Tight junctions' role in creating barriers, like in the blood-brain barrier, distinguishes them, making 'c' the correct junction type.

Correct Answer: C

Rationale: Long bones, like the femur or humerus, are longer than wide, designed for support and movement via levers. Short bones are cuboidal (e.g., carpals), flat bones are thin (e.g., skull), and irregular bones are complex (e.g., vertebrae). Long bones' length-to-width ratio, per bone classification, makes 'c' correct.

Correct Answer: C

Rationale: Eight cranial bones form the skull's braincase: frontal, 2 parietals, 2 temporals, occipital, sphenoid, ethmoid. Options 10, 12, 14 (a, b, d) may confuse with facial bones (14 total), but cranial-specific is 8. This count, per skull anatomy, makes 'c' correct.

Correct Answer: A

Rationale: Facial bones include maxilla (upper jaw) and mandible (lower jaw), shaping the face (14 total). Humerus/femur are limb, scapula/clavicle are pectoral girdle, occipital/parietal are cranial not facial. Maxilla/mandible's facial role, per skull, makes 'a' correct.

Correct Answer: C

Rationale: Hyaline cartilage, smooth and glassy, forms costal cartilage in the rib cage, connecting ribs to sternum, flexible yet supportive. Elastic is in ears, fibrocartilage in discs neither fit ribs. Hyaline's prevalence, per thorax, makes 'c' correct.