Final answer:
Bath water at 106 °F: thermal stimulus. Acetylcholine, perfume, epinephrine, and lemon juice: chemical stimuli. A punch on the arm: mechanical stimulus.
Step-by-step explanation:
In order to characterize each of the following stimuli as mechanical, chemical, or thermal, we need to consider the type of receptor involved. Bath water at 106 °F is a thermal stimulus, as it is sensed through thermoreceptors that detect temperature. Acetylcholine is a chemical stimulus, as it is detected by chemoreceptors. A hint of perfume is also a chemical stimulus, detected by chemoreceptors. Epinephrine is a chemical stimulus as well, detected by chemoreceptors. Lemon juice is a chemical stimulus, as it activates taste receptors. Finally, a punch on the arm is a mechanical stimulus, detected by mechanoreceptors.