walrus: either of two large northern marine mammals having ivory tusks and tough hide over thick blubber
placental: mammals having a placenta; all mammals except monotremes and marsupials
answer: the principal pleading by the defendant in response to plaintiff's complaint; in criminal law it consists of the defendant's plea of `guilty' or `not guilty' (or nolo contendere); in civil law it must contain denials of all allegations in the plaintiff's complaint that the defendant hopes to controvert and it can contain affirmative defenses or counterclaims