The species P and Q of wild animals are found exclusively in a 'particular area'. The species R of wild animals is listed in Red data book of India whereas species S of wild animals no longer exists anywhere on the earth.
(b) What are the species like R known as ?
The species which are facing the risk of extinction are called endangered species (R).
Red Data Book is the 'book' (or publication) which keeps a record of all the endangered animals, plants and other species.