Answer:
1. The digestive system works very closely with the circulatory system to get the absorbed nutrients distributed through your body. The circulatory system also carries chemical signals from your endocrine system that control the speed of digestion. The digestive system also works in parallel with your excretory system (kidneys and urination).
2. The human respiratory and circulatory systems work together to supply the body with oxygen and get rid of waste carbon dioxide. While the former deals with air and the latter with blood, they work together seamlessly by coordinating the functions of the many parts of each system.
3. The respiratory system also works closely with all other systems of the body 2. The respiratory system provides oxygen for all body parts. It also removes carbon dioxide from the muscular, digestive, skeletal, circulatory, urinary and nervous systems 2. This system includes the nose, larynx, trachea and the lungs.
