circulatory system

A structure in the heart and some veins that prevents the blood from flowing backwards.

A colorless, odorless reactive gas, the chemical element of atomic number 8 and the life-supporting component of the air.

any of the tubes forming part of the blood circulation system of thebody, carrying in most cases oxygen-depleted blood toward the heart.

carbon dioxide is found in air, we get rid of it and we exhale carbon dioxide.

Each of the two main chambers of the heart, left and right. ( there are 4 chambers they are atrium, ventricle.)