Triglycerides' Properties for Energy Storage

Steps:

• Identify key requirements for energy stores: compact, hydrophobic to avoid water interactions, and low density to prevent buoyancy issues in organisms.
• Evaluate feature 1 (liquid/solid state): Affects usability but not core storage suitability.
• Evaluate feature 2 (high C-H bonds): Indicates energy richness but not why suitable for storage.
• Evaluate features 3 and 4 (insoluble, less dense): Enable aggregation without dissolving or sinking.

Why D is correct:

• Insolubility (3) allows triglycerides to form anhydrous droplets in cells without osmotic disruption, per lipid biochemistry; low density (4) ensures flotation in cytoplasm, optimizing space per the principle of neutral buoyancy in adipose tissue.

Why the others are wrong:

• A: Feature 1 influences form (e.g., fats/oils) but not storage efficiency; 2 provides energy but doesn't address storage logistics.
• B: Feature 1 is secondary; 4 aids buoyancy, but lacks hydrophobicity essential for isolation.
• C: Feature 2 is energetic but irrelevant to storage; 3 is key, but pairing ignores density's role in positioning.

Final answer: D