In a forward collision, the driver and everyone else's head is thrusted back (because the energy transfer from one car to another [i.e. the Inertia] ).. the head rest is there to stop the heads from moving to far back that it could break your neck.
The answer is C!!!!!!!!!!!!!!!!!!!
An example of an atom that has no charge is one that has a. 2 protons, 2 electrons, and 1 neutron.
To be neutral an atom must have the <em>same number</em> of protons (+) and electrons (-).
Only then will the <em>charges cancel</em> and give a neutral atom.
Its 470mg k dude or dudette