Identify the morphemes in the word cats and classify the affix type.

• A. cats (root) + -s
• B. cat + -ing (derivational suffix)
• C. cat + -er (agent suffix)
• D. cat (root) + -s (inflectional suffix)

Answer: (D)

When you break down a word into morphemes, the base meaning comes from the root and any endings signal grammatical information. In cats, there are two morphemes: the root cat and the suffix -s. The root provides the basic meaning of the animal, while the ending -s marks plural, indicating more than one. Because this suffix adds grammatical information (number) without changing the word into a different part of speech or creating a new word, it’s an inflectional suffix. So the correct breakdown is cat (root) + -s (inflectional suffix). The root isn’t cats—the root is cat—and the -s here isn’t a derivational suffix like -ing or -er, which would change the form or meaning more than just number.