the hollow muscular organ located behind the sternum and between the lungs; its rhythmic contractions move the blood through the body

胸骨の後ろ、肺の間に位置する中空の筋肉でできた器官。そのリズミカルな収縮が体内に血液を送り出す

any warm-blooded vertebrate having the skin more or less covered with hair; young are born alive except for the small subclass of monotremes and nourished with milk

少なくともある程度毛で覆われた皮膚を持つ恒温動物の脊椎動物の総称。モノトレム類という小さな亜目を除き、子供は生きたまま生まれ、ミルクで育てられる。