Which of the following has the most primitive respiratory system? by Sunday | Jun 29 | Biology WAEC | 0 comments A. Rat B. Fish C. Toad D. Grasshopper E. Lizard Correct Answer: Option D – Grasshopper Users Also Read These:In birds, loss of appetite, respiratory difficulties…One primitive feature of the coelenterates is the…A pulley system has three pulleys in the fixed block…The exchange of gases between the environment and…SS2 Biology Lesson Note on Respiratory System