A refrigerator is used for keeping food fresh for a long period of time.
Air, heat and light cause dried food to spoil.
A refrigerator is protection from air, heat and light.
A working refrigerator is good protection from what?
  - Electric devices
  - plastic
  - Abnormal cell growth
  - darkness
  - Temperature changing
  - a pathogens
  - air, light and heat
  - cold