What two human body systems perform similar functions? Endocrine and excretory

Excretory and digestive

Respiratory and endocrine

Circulatory and skeletal

For example, the respiratory system and the circulatory system work closely together to deliver oxygen to cells and to get rid of the carbon dioxide the cells produce. The circulatory system picks up oxygen in the lungs and drops it off in the tissues, then performs the reverse service for carbon dioxide.

Explanation:

The answer is all of them if you are doing study island

Explanation:

The explanation they give is:

All of the organ systems within the human body are interrelated in some way, and they play vital roles in processes that occur within the human body.

All of the listed paired organ systems possess functions which are directly interrelated. The respiratory system takes in oxygen, and the circulatory system carries it throughout the body. The excretory system disposes of the solid waste that is generated by the digestive system. The endocrine system makes hormones that are used by the reproductive system. The muscular system allows the bones of the skeletal system to move.