I read the site and look at the picture in the site.It's talk about the heart and the circulation system.I like the website because I like to learned a few of people's body.It can let me study better.After I raed the site I learned:the heartbeat is because the heart is cleaning our blood.There are two color of blood.One is blue and the other is red.The blue blood are the dirty blood they need to clean.Than the red blood is the clean blood.The heart has cleaned,so it is the circulation system of the heart.
the picture is the photo of the heart circulation system
I read the site and look at the picture in the site.The site is tak about there are two kids of circulation in the heart.One is clean the blood.The other is arteries and veins use to get oxygen-rich blood to your organs and tissues. After I read the site I learned: ourarteries and veins use to get oxygen-rich blood to your organs and tissues. and our blood can have more smoothly.
the picture is the photo of the haert and its uses