What does "soporific" describe?

The term "soporific" specifically refers to something that induces sleep or has a calming effect, leading to drowsiness. It originates from the Latin word "sopor," which means deep sleep. When describing substances, like certain medications or activities that promote relaxation, "soporific" conveys their ability to encourage a state of sleepiness. Thus, the choice that states it causes sleep accurately captures the essence of the word, distinguishing it from terms related to stimulation or increased alertness. This understanding emphasizes the concept of inducing calm rather than excitement or energy.