Which chemical group is described as contributing to natural pain relief and feelings of euphoria or well-being?

### Why this is right Endogenous opioids are described as natural pain-relieving and pleasure-inducing chemicals that contribute to euphoria and well-being. ### The concept The reward system involves more than one chemical signal. Dopamine is associated with rewarding stimuli and motivation, while endogenous opioids contribute to pain relief and pleasure-related feelings. ### The other options - **Glutamate**: is listed as a neurotransmitter involved in modulating synaptic strength and learning. - **Acetylcholine**: is also listed in relation to learning, not as the named natural pain-relieving chemical group. - **Sensory receptors**: detect stimuli; they are not the pleasure-inducing chemicals described here. ### Terms - **Endogenous opioids**: naturally occurring chemicals that contribute to pain relief and pleasure. - **Euphoria**: an intense feeling of well-being or pleasure. ### Remember Dopamine is tied to reward and motivation; endogenous opioids contribute to pain relief and pleasure.