Which of the elements below have seven electrons in their outermost energy levels? A.) Cr, Mn, and Fe B.) Br, I, and Ci C.) O, S, and Se D.) He, Ne, and Ar

To use anything transparent

Isso9

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