Which morpheme, when added, alters grammatical function without changing the root word’s category?

💡 Explanation:

The suffix '-ed' is an inflectional morpheme; it adds a grammatical function (past tense) but does not change the word's lexical category (a verb like 'walk' remains a verb in 'walked'). Derivational morphemes (un-, -tion, -ly) typically create a word with a new core meaning or change its lexical category (e.g., 'act' (verb) to 'action' (noun)).