Planetary ring systems can result from the destruction of a moon orbiting within the Roche limit of a planet. Choose the statement that best describes how a moon can be destroyed within this limit. a. The chance of collision with other objects increases. b. The forces binding the moon together are exceeded by the tidal forces from the planet. c. The planet's magnetic field rips the moon apart. d. Drag from the atmosphere causes the moon to break up.

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -

The rocks expand when there hot/warm  and contract when they are cold.