Final answer:
Peripheral and central chemoreceptors both monitor and respond to changes in blood oxygen, carbon dioxide, and pH levels. If blood oxygen levels become low, both types of chemoreceptors stimulate an increase in respiratory activity.
Step-by-step explanation:
Both peripheral and central chemoreceptors are responsible for monitoring and responding to changes in blood levels of oxygen, carbon dioxide, and hydrogen ions (pH). Peripheral chemoreceptors sense large changes in blood oxygen levels, while central chemoreceptors are located in the brain and respond to chemical and pH changes in the blood. When blood oxygen levels become low, both types of chemoreceptors stimulate an increase in respiratory activity.