Respuesta :
Answer:
respiratory system. it is the system that helps you breathe/lets oxygen in body
Answer:
D. Respiratory
Explanation:
Respiratory is a pertaining to respiration; respiratory assistance. The respiratory system is made up of the nose, pharynx, trachea, lungs, bronchi, and alveoli.
Circulatory is relating to circulatory system or to circulation of the blood.
Therefore, the correct answer is d. respiratory.