Which morpheme changes the form of a word without changing its meaning?

The inflectional morpheme is the correct choice because it modifies a word's form to indicate grammatical features such as tense, mood, aspect, number, or gender, without altering the original meaning of the word. For example, adding the suffix "-s" to a noun creates a plural form (e.g., "cat" becomes "cats") but does not change what the word represents, which remains a feline. Similarly, adding "-ed" to a verb (e.g., "walk" becomes "walked") indicates past tense with no change in the core idea of walking.

In contrast, derivational morphemes create new words and often alter the meaning. For instance, adding "-ness" to "happy" to form "happiness" creates a different concept entirely. Free morphemes are standalone words, while bound morphemes cannot exist independently and always attach to other morphemes. However, only inflectional morphemes focus solely on grammatical adjustments rather than meaning alteration.