What are the features: respiratory system, circulatory system, reproductive system

All these systems are characteristic of many representatives of the animal kingdom. The respiratory and circulatory systems are necessary to provide all tissues and organs of the body with oxygen. Also, due to the peculiarities of red blood cells, carbon dioxide is removed from the tissues. The reproductive system is important not only for the reproduction of organisms. The reproductive system has some sex glands. They secrete a number of hormones that can affect other internal organs and organ systems of the animal.