Este tipo de desarrollo se refiere al desarrollo de la mente es la capacidad de pensar razonar y usar el lenguaje informal ideas que es?

Dis the

Answer(a)   the matererials that are in contact, the two materials and the nature of their surfaces/// (b)/// the force pushing the two surfaces together, pushing the surfaces together causes the more of the asperities to come together and increases the surface area in contact with each other