Answer:
The correct answer is peripheral chemoreceptors.
Step-by-step explanation:
The peripheral chemoreceptors are named so as they are considered as the sensory extensions of the PNS into the blood vessels where they determine variations in the chemical quantities. These polymodal sensors react towards the changes in the number of blood properties, comprising the peripheral chemoreceptors in air versus water breathers.
The peripheral chemoreceptors comprise carotid and aortic bodies. The aortic body determines variations in the carbon dioxide and oxygen present in the blood, however, not the pH, while the carotid body determines all the three.