Is concrete a Natural Material or Synthetic Material

What is the equilibrium constant of aa+bb=cc+dd

Why is permeable soil best for plants that need a lot of drainage?

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.