How can we bring back extinct animals and organisms – such as dinosaurs, dodo birds or the Woolly Mammoth for instance?

Question: How can we bring back extinct animals and organisms - such as dinosaurs, dodo birds or the Woolly Mammoth for instance?
- Keywords:
  animal,
  dinosaur,
  extinct,
  mammoth
Asked by Maximus to Ed, Kerrianne, Nina, Oli, yoyehudi on 9 Nov 2017. This question was also asked by Morgz.
- Oli Wilson answered on 9 Nov 2017:
  
  It’s pretty hard to do, unfortunately! Although we do have DNA from dodos and mammoths (in the case of mammoths, it’s even been conveniently frozen!), we haven’t got any from dinosaurs. DNA also starts to break down with time, and after 1000 years most of it’s gone. That probably means that we might struggle to bring back mammoths, but maybe dodos?
  The other thing that has recently started being used is called crispr – it’s a way of editing genes! That might mean it’s possible to get a pigeon or another bird that’s similar to a dodo, then stick in the bits of dodo DNA we can find and hope that what we get is a dodo. It won’t be easy, and it won’t be 100% the same as what went extinct (extinction is forever!), but it might help us realise how cool these things we’ve lost are and were 🙂

Question: How can we bring back extinct animals and organisms - such as dinosaurs, dodo birds or the Woolly Mammoth for instance?