An organism has copies of each gene.

Simple harmonic motion wind energy circulation best answer from the choices

Because its reliable.   there is no pollution  the chances of a radiation leak is low

That big glowy thing in the sky is called the sun

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