Answer: Chemoreceptors
Step-by-step explanation:
It is Chemoreceptors because Chemoreceptors are receptors found in the pharynx and oral cavity that tranduces chemical substances or detect stimulus and send it to the brain and it is converted to biological signal. It is sensitive to chemicals like carbondioxide and detect changes in normal environment for carbondioxide increase or reduction in oxygen in the bloof and then send it to the brain for interpretation. Chemical changes I their environment stimulate them.