counting with zero or one solid stays tend to lose those mammal
small_mammal is mammal. mammals has not legs dryopithecus is not mammal. mammals has not four_limbs losing_one's_balance is not action_performed_by_animals. losing_one's_balance is action_performed_by_animals. most_mammals has not seven_neck_bones mammal_whole_body is not tangible_thing. all_mammals is not vertebrates. small_mammal is not mammal.