How do van der Waals attractions enable geckos to adhere to surfaces?

• A. Van der Waals attractions are too weak to affect gecko adhesion.
• B. Van der Waals attractions make gecko feet hydrophobic, preventing adhesion.
• C. Van der Waals attractions create ionic bonds between gecko feet and surfaces.
• D. Van der Waals attractions allow gecko feet to form weak bonds with surfaces, enabling adhesion.

Answer: (D)