1. One similarity between respiratory system and excretory system.
2. One similarity between respiratory system and reproductive system.
1. Both the respiratory system and the excretory system are involved in removing waste products from the body. The respiratory system removes carbon dioxide, while the excretory system removes waste products such as urea and excess salts through urine.
2. Both the respiratory system and the reproductive system are involved in the exchange of gases. The respiratory system exchanges oxygen and carbon dioxide during respiration, while the reproductive system exchanges genetic material during fertilization.