Why is it that in our universe, only gravity extends to infinity, whereas electromagnetic forces are much more limited in extent? A) Electromagnetic forces from charged particles will move other charged particles around to produce a uniform charge distribution and therefore zero electromagnetic forces, whereas gravity concentrates mass and enhances the overall gravity force. B) All atoms are electrically neutral so, in reality, the electromagnetic force never reaches beyond the size of an atomic nucleus. C) Gravity and electromagnetism are one and the same force, with electromagnetic effects extending over limited spatial ranges and transforming into gravitational forces at large distances from matter. D) Electromagnetic forces from positive charges are canceled by negative charges, whereas there are no negative “masses” to cancel the gravitational force. 19. Over what time during the Big Bang were all four fundamental forces unified? 20. Where and how was most of the helium in t