The morpheme "-ate" is a suffix that can change a word's part of speech, typically transforming nouns into verbs. In the case of the noun "stimulus," adding the suffix "-ate" changes it to "stimulate," which is a verb.
To summarize:
- "Stimulus" (noun) refers to something that incites or accelerates an action or reaction.
- "Stimulate" (verb) means to cause or increase a response or activity.
Thus, the addition of "-ate" shifts the part of speech from a noun to a verb.