| It can be said that our body is like a society which five internal organs, such as the heart, a lung, liver, the kidney, and the pancreas including a brain, intestines, muscles, a bone, etc. help each other mutually and is alive. Moreover, we are helped by parents, the school teacher, and many people that work at the meeting of the other company, and are alive. Moreover, we are helped by parents, the school teachers, and many people working at the society, and are alive. It seems that we pass over in many cases, without noticing that we are related mutually. Then, this time, let's study about the heart and a lung. |