The dog has always been considered man' s best friend.Always noted for being particularly faithful in watching over children , he also has his place by the fireside , in the cow pasture , on the sheep range (放牧区) , and beside the hunter in forest.He is easy to train , works hard , and often performs astonishing feats.And in the frozen polar regions he was once the principal motive power , before being lately displaced by the plane and helicopter. Because he howls or whines in the presence of impending death , the dog was once thought to have supernatural powers and believed to be capable of seeing gods and ghosts invisible to men.Actually , the basis for these beliefs lies in the hound' s sensibility to people' s feelings and his superior hearing ability and sense of smell , which enable him to detect signs hidden from human observation.His record of saving lives is outstanding , for he often gives warning of fire and other dangers not noticed by his master. The dog' s major contribution , however , has been to medical research.Both his diet and his structure are comparable to those of the human being , and so he has been the subject of countless demonstrations and experiments.Open-heart surgery has been made possible largely because of the dog.But his sacrifice has repaid his own species as well by safeguarding it from rabies (狂犬病) , distemper , and other diseases. 36.The dog has always been noted for( ).
A.protecting children B.assisting shepherds C.helping hunters D.herding cattle