Answer:
(VEE-nuh KAY-vuh) A large vein that carries blood to the heart from other areas of the body. The vena cava has two parts: the superior vena cava and the inferior vena cava. The superior vena cava carries blood from the head, neck, arms, and chest.
The Cỉculatory system is an organ system that permits blood to everywhere in the body and transport nutrients, oxygen, carbon dioxide, ...to help fighting diseases ,.... The main parts of the Circulatory system are heart , lungs , veins , vessels, arteries,...
As you go up in an ecosystem the bigger animals have less energy. While the organisms down at the bottom like plants that create their own energy have greater amounts. This is because energy is rated doing everyday things. As energy travels up the food pyramid, it looses more and more energy. This is knower as the 10% rule. In which every time you go up 10% of energy is lost.