この商品を友人に教える:
Heart Bold Kids
Heart
Bold Kids
The heart has four chambers. Each chamber pumps blood to different parts of the body. The heart rhythm is caused by the activity of the valves in each chamber, known as open-and-close valves.
この商品を友人に教える:
The heart has four chambers. Each chamber pumps blood to different parts of the body. The heart rhythm is caused by the activity of the valves in each chamber, known as open-and-close valves.
