Write TRUE if the statement is correct and FALSE if it is incorrect. Write your answer on the space provided for. 11. The main organ of the respiratory system is the bronchi 12. The cardiac muscles control the movement of the digestive tract and bladder 13. The brain controls the sweat glands of the body. 14. The blood transport oxygen and carries waste materials from the cells. 15. The circulatory system produces millions of blood cells needed by the body.​