How can caterpillars change into butterflies?

Question: How can caterpillars change into butterflies?
- Keywords:
  butterfly,
  caterpillar,
  insect
Asked by aka Agent Jellybean to Anna, Hayley, Iain, Rebecca on 22 Jun 2015.
- Rebecca Jones answered on 22 Jun 2015:
  
  When caterpillars are ready to turn into butterflies, they stop eating and spin a cocoon or chrysalis, normally hanging upside down from a leaf or twig. Within its protective shell, the caterpillar then transforms into a butterfly. This process is called metamorphosis.

Question: How can caterpillars change into butterflies?