1 He has to keep his identity secret because graffiti is illegal. He uses a pseudonym to identify his work but not himself.
2 He had a difficult childhood so he did graffiti to make himself feel better and to give himself a voice.
3 Because he wasn’t very good with a spray can and also because it was quicker to use a stencil.
4 Banksy.
5 That he’s anti-war.
6 The animals’.
7 He likes to use it to create his own work.
8 Yes, it’s worth a lot of money. Famous people pay a lot for it.