[Solved] The main difference between conductors and insulators is in terms of A) protons. B) neutrons. C) valence or conduction electrons. D) atoms. E) None of the other choices is correct. Voided: Emptied or evacuated, often used in medical contexts to refer to the expulsion of waste fluid from the body. Nephron: The structural and functional unit of the kidney. Kidney: A pair of organs in the urinary system that filter waste products from the blood and excrete them in urine. Microscopic Units: Small units of measurement typically used to describe dimensions of cells and microorganisms, not visible to the naked eye.