Decide which type of relative clauses the following sentences contain. Mark them with D (defining) or ND (non-defining).
1) The national park, which is situated in this region, is always crowded ___
2) That is the place where we went last year ___
3) These were animals which can be found in the area ___
4) The Red Book is a book which registers endangered animal species ___
5) Many of the visitors to the park, who want to see wild animals, prefer to come when the weather is fine ___
6) Yesterday the government, which was in session, developed several laws concerning pro- tection of animals and plants ___