Which stimuli is detected by a chemoreceptor?

Carbon dioxide concentration in blood, Hydrogen ion concentration, drugs, and some other chemicals.

Explanation:

The chemoreceptor is a type of sensory receptor that detects and changes chemical material into biological signals. Generally, this receptor detects toxic chemicals in internal as well as from the external environment and sends the information to CNS. Generally, chemoreceptors are classified into two groups one is called distance chemoreceptors such as olfactory receptor neurons and the other is called direct chemoreceptors such as the taste receptor of the gustatory system.