As stated in the article, “As Sticky as a Gecko . . . but Ten Times Stronger!,” the adhesive the researchers developed sticks best when it is pulled down parallel to the surface. What type of adhesion is this called?

A force applied parallel to a surface acts along it, rather than pulling straight away from it. Adhesion that is strongest under this kind of sideways pulling force is called shear adhesion, so the correct choice is shear adhesion.

AI-written and checked against the verified answer.