An opioid peptide produced in the brain, especially in the pituitary gland, that blocks the sensation of pain is:

1. substance P

2. beta-endorphin

3. nicotine

4. neuropeptide

Odors can alter our moods:

1. Because sensory input from olfaction is routed through the limbic system.

2. Because odors act as neurotransmitters and alter brain chemistry.

3. Because odors are satisfying to our sense of hunger.

4. Odors do not alter mood.