Collagen Tensile Strength Determinants

Steps:

• Identify key structural features of collagen: cross-linking, amino acid composition, fibril organization, and mineralization.
• Recall that tensile strength depends on intermolecular bonds and alignment, not surface properties or external factors.
• Evaluate each feature: cross-links (feature 1) enhance stability; specific residues like hydroxyproline (feature 3) stabilize helices.
• Eliminate irrelevant features: diameter variations (2) and hydration (4) minimally impact intrinsic strength.

Why B is correct:

• Tensile strength follows the rule that covalent cross-links and proline hydroxylation directly reinforce triple helix integrity per biochemical models of fibril mechanics.

Why the others are wrong:

• A includes irrelevant feature 2 (fibril diameter affects flexibility, not core strength).
• C omits essential feature 1 (cross-links are primary for load-bearing).
• D excludes feature 1 while adding irrelevant 4 (mineralization alters bone composite, not pure collagen).

Not enough information on exact features 1-4, but based on standard biology.

Final answer: B